Taqlid means for one to refer to an expert in a certain field for enlightenment. The ulema have comprehensively explained all of the reasoning for their judgments in their detailed books. Also, the fact that everyone is responsible for his/her own actions is in no way in conflict with referring to the marjas for advice, and when it is said that we have to follow the marjas, we are actually following the imams, not the marjas.
Your question actually, can be divided into a few sections and a conclusion: 1- Questions about taqlid itself 2-Expressing the methods used to deduce Islamic rulings 3- Who holds the responsibility for our acts 4- Our resurrection with the imams, not the marjas, and finally the conclusion of only referring to the marjas for information, not for following them.
We will discuss each of these sections respectively:
1) In fiqhi terms, taqlid means for one to refer to the experts in a certain field on an issue related to that field. This is a matter accepted and practiced by all in different fields such as medicine (people go to the doctor) and doesn’t belong only to fiqh. The Quran and hadiths also confirm this subject. Of course, it isn't permissible for one to follow others, regardless of who the person he/she wants to follow is, in the roots and fundamentals of religion (usuluddin), and can only do so with the branches of religion/actions of belief (furu’uddin). The fundamentals of religion must be reached with one’s own insight, understanding and effort in research  , but it can be concluded by Quranic verses  and hadiths  that regarding Islamic laws and rulings which aren’t part of the fundamentals, in the case of not being a mujtahid (one who has the ability of deriving Islamic law from its sources) or not practicing ihtiyat (acting on such precaution that one can be sure that he/she has fulfilled his/her Islamic duty), it is obligatory for one to refer to the experts in jurisprudence and follow one of them whom they are sure is pious  ; in this case they will pardoned by Allah (swt) in the case of their marja’s verdict being wrong  . Of course, jurisprudence doesn’t belong to a certain group of people and anyone who desires can spend the time needed and gain the knowledge and academic requirements necessary for it. What is more interesting is that once a mujtahid, one can no longer practice taqlid, and it becomes forbidden. You can refer to question 974 (site:1045) of this website for more information on taqlid.
2) There are thousands of fiqh books written by the ulema and scholars in which they have explained all of their reasoning for their judgments in detail  , yet not all have the ability of understanding everything written in them, because various prerequisites are required, just like any other field of study, that is why these scholars have also compiled only their final verdicts all in one book called the risalah or tawdihul-masa’el in which normal people can use to learn the judgments of their marjas.
Now if someone chooses to learn about the reasoning behind his/her marja’s verdict, if he/she is learned enough in jurisprudence and has had studies in this field, he/she can refer to the detailed books mentioned above, and if not, can go to those who are at an intermediate level in these studies, so that they can explain what has been written in these books.
Therefore, according to this, what you said about the marjas not stating the reasoning for their judgments isn't true and they actually have mentioned it in their books. On the other hand, one can't expect a marja to explain the reasons behind each and every one of their verdicts to every one of those following them! The same goes for doctors’ patients; when they go to a good doctor that they trust in, they in no way expect the doctor to explain how the drugs on the prescription are made, what their effects are once they enter the body, how they make the body feel better, how the body reacts to them, etc. That is because even if the doctor explains everything in detail, they won't understand.
3) What you stated about the Quran saying that every person is responsible for his/her own actions, is absolutely true, yet these verses have nothing to do with the taqlid that Islam has acknowledged, because first of all, none of them say that it is forbidden to follow pious Islamic scholars, and secondly, if your reasoning was to apply to Islamic scholars, it would also have to apply to the prophets, and we wouldn’t be allowed to follow them either, because every person is responsible for his/her own actions and as the Quran says: “If they deny you (the holy prophet (pbuh)), say," My deeds belong to me and your deeds belong to you: you are absolved of what I do and I am absolved of what you do.”  .
Please pay attention that blindly following others off of bias isn't acceptable in Islam, and the Quran deeply scolds those kafirs and mushriks who would accept no reasoning whatsoever and would only follow their ancestors’ beliefs  . On the other hand, not only is following Islamic scholars something everyone comprehends and accepts  , but is also one ordered to by the imams. Conclusion: Not every person is qualified to be followed regarding Islamic issues, therefore if it ever happens that someone issues fatwas that have no Quranic or hadithic basis, he can't be followed. There is a chapter in the hadith book Wasa’ilu Shia of Sheikh Hurr Al-Ameli, named “The impermissibility of following anyone other than the infallibles in cases of him giving his own opinion on an issue that isn't based on the imam’s sayings”  in which he presents this subject and lists some hadiths regarding it.
Therefore according to the Shia, taqlid means that after one reaches the fundamentals of Islam through inquiry and research, thus believing in Allah (swt) and the prophet (pbuh) and the imams, he/she needs to refer to Islamic scholars to learn the opinion of the imams on issues in which he/she doesn’t know Islam’s viewpoint on; Islamic scholars who he/she is sure are pious  .
Of course, if one gets his/her answer from a mujtahid (Islamic scholar) and yet doesn’t act according to it, the mujtahid holds no responsibility towards him/her. Also, if a mujtahid commits actions that he isn't supposed to, disqualifying him from his current rank, the one following him will only have to follow another mujtahid instead of him, and all of the previous acts eg. prayer he had done according to the disqualified mujtahid’s fatwas are accepted, having no need to be repeated and made up for. 
4) There is no doubt that every person will indeed be resurrected with his/her imam, but as was said before, it is the imams who have asked us to follow Islamic scholars, and that is the main reason why we do so.
Therefore, following these scholars can be considered the cause for us being resurrected with the imams. Also, being resurrected with the imams doesn't mean one can't be resurrected with other righteous individuals at the same time, as the Quran says: "Whoever obeys Allah and the Apostle they are with those whom Allah has blessed, including the prophets and the truthful, the martyrs and the righteous, and excellent companions are they!"  . There is even a hadith that states that even if a person likes a stone, he will be resurrected with it on the Day of Judgment  . According to this, there are chances that some people will be resurrected with more than one person, provided that all of them are on the same path.
5) Regarding your conclusion, one must say that we completely follow Islamic scholars because that is how we have been ordered by the imams themselves and in other words, we don't follow them because we believe they are to be followed, but because the imams have told us that they must be followed, and that is because they strive to reach and reflect the imams' viewpoints on Islamic issues, not their own. In many cases, they themselves don't know the reason for a certain Islamic law and all they know is that it is what the imams have demanded. This is why according to the Shia point of view, in contrast to the Sunni point of view, using the method of “qiyas” to obtain Islamic rulings is strictly prohibited. For instance, sometimes it happens that we don’t know the Islamic ruling of a certain issue, but since there is another issue that we do know the ruling of, and at the same time the two issues are similar in some dimensions, here it isn't permissible to say that the ruling of the two is the same just because they have some similarities, because this act is qiyas and isn't acknowledged in Shia jurisprudence and the imams have severely prohibited it. So only the Quran and the prophet (pbuh) and the imam’s sayings are to be used to obtain Islamic rulings.
Therefore, as you put it, referring to marjas is for enlightenment, but once we refer to the marjas and learn what the imams have wanted from us regarding a certain issue, and we believe that the imams must be followed, there is no longer any choice but to follow and act accordingly, and this in no way contradicts our right to do further research about the ruling.
It is on this basis that in every era, the scholars of that era would both analyze and criticize the viewpoints of past and present scholars, and wouldn’t believe in a viewpoint just because a certain scholar had said so. You can do research on Islamic issues as much as your Islamic information allows you, and in the case of not reaching a certain conclusion, you can ask your question from this site.
 For further information, see: index: Practicing taqlid on the fundamentals of Islam, question 322 (site:1460).
 For instance: Nahl:43, Anbiya:7, Tawbah:122.
 See: Mohammad Baqir Majlesi, Biharul-Anwar, pp.81-105.
 Ruhollah Khomeini, Ibid, Issue 3.
 As was said before, this is a reasonable matter comprehended and accepted by all.
 You can refer to the Jame Feqh Ahlul Bayt CD by for more information.
 Maidah:104, Zukhruf:28, Yunus:78, Anbiya:53 etc.
 Meaning that people refer to the experts in fields they aren’t experts in.
 Muhammad ibn Hasan Hurr al-Ameli, Wasaelul-Shia, vol.27, pg.124.
 Ruhollah Khomeini, Tahrirul-Wasilah, pg.5, issue 3.
 Ibid, pg.8, issue 18; pg.10 issue 29.
 Muhammad ibn Hasan Hurr Ameli, Wasaelul-Shia, vol.14, pg.503, hadith 19694.