There's a lecture you delivered about barzakh. In it you mention believers will be given an option to return to this world and help the imam:

1: Is the option given to specific believers in the barzakh or all?
2: if a believer accepts, comes to this life, do they remember the barzakh? Will their status be elevated when they return to the afterlife?
3: What are the benefits to reciting dua Al faraj? As in, Allahmua Kul Liwaliyak Al hujja ibn Al Hassan.

1- The option will be given to high ranking believers, those with pure faith, with pure Aqidah, and those who recite Du’a Ahd 40 days.
2- The hadiths don’t mention whether they will remember the Barzakh or not, but we can assume that yes they will remember it. And they will be brought back as adults not newborns. When they die again, their status will be elevated because they supported their Imam.
3- The benefits are that one becomes closer to the Imam of His time, one’s sins are forgiven, and this prayer serves to hasten the reappearance of the Imam.