I disagree, its obvious from the beginning that Minato's death has splintered the group, some have accepted and moved on, others are still trying to come to terms, and both Yukari and Aigis are obviously in denial. Sure they bonded but we're talking about something absolutely fantastic falling into their hands and this was just right after the revelation about the Shadow Minato they chased throughout the Abyss of Time and how the whole group of them was still coming to terms with his death only to suddenly be told they have a shot of going back and stopping him from making his choice. The group bonded but they still haven't come to grips with Minato's death and the choice was about his death so freindship be damned the group is easily shown to be in an emotionally vulnerable moment. I felt the infighting made sense, especially since P3's cast never bonded into a family per se, they are more like comrade, fellow soldiers that survived a war.
Not going to disagree there,. even I felt it was kind of far fetched the first time I played through but considering how many wacky plot threads and other bizarre crap happens in the series let alone the MegaTen franchise as a whole, I simply rolled with it. Not saying it wasn't poorly executed but I certainly wasn't as bothered by it as you were, I mean I just finished watching Minato beat up the physical embodiment of death, which happens to be our moon, with the power of love and friendship, I'm not going to question a rip in space and time caused by the party feeling mopey about the MC's death.Also, the setup for the time travel is weak. It just suddenly pops into existence at the start, and then shuts down at the end. No foreshadowing, no explanation, no real closure. Just voila. Time Travel.
To me it was pretty obvious that Yukari and the MC were meant to be together, they have many tender moments together in just the main story whereas the other characters got zero air time. Her special date events are also more personal and intimate compared to the other characters if you do a side by side comparison. Likewise Yukari needs the MC as a romantic relationship compared to the others. The other girls dealt with issues about their own self-worth and choices they made but Yukari's Social Link deals with her inability to be intimate with men because she doesn't want to be like her mother. Her family issues seriously screwed her up and for her, having a real romance works.Also, it makes Player Choice of romance options pointless, which I also hate.
While the non-party member girls could all certainly work either way, I always felt the ability to have relationships with Fuuka and Mitsuru felt forced cause I could see neither of them really being motivated by love. They don't really need it to be who they are and thus the actual relationships while sweet, always felt forced to me. I really can't see Mitsuru falling in love, she strikes me as a career woman first and I am alright with that, besides she needs to hook up with Akihiko anyway.
I always imagine the MC was a hound dog and took them all as part of his harem. I mean let's face it the dating mechanics in FES are not as good as later installments. Though I would point out that Yukari being devastated like she was doesn't necessarily mean she's the canon partner, she may have simply had unrequited feelings for him and lost the chance to be with him, so he could have dated any of them. It's not like The Answer flat out states they were an official couple so the dating choices still largely stand.
Technically Minato didn't die at the battle, Ryoji never said he wouldn't die later and Minato survived on pure willpower alone for several months after the fateful day. So Ryoji didn't necessarily lie about it. Also Mitsuru does state that they took him to the hospitable but he simply stopped, even Chidori was on her way to the morgue when they finally noticed the heartbeat and then put her on life support. I don't think it happened for Minato but who knows, he may still be in a hospital owned by the Kirijo Group, I don't remember the group mentioning a burial. Of anything, the revelation about Erebus would most likely have made the group choose to formally bury him anyway if he hasn't already because even they understand that beating Erebus may not happen in their lifetime.
I once read a fairly complex essay listing a ton of minor things that were hinted or showed themes trending towards his survival. I wish I could find it again, but it was something I read about five years ago, and I have no clue where it was. There's also the heavy stress from Ryoji in the chat with SEES after the victory that Minato wasn't going to die as a result of the battle, that's like 90% of what he's saying there. It may have been a theory, but I felt it was open enough to leave it a choice.
There's also the fact that I find it kind of hard to believe that Mitsuru would let him die (especially if you romanced her). I think it more likely she'd take him to a hospital and keep him on life support indefinitely (not that I think it would matter, I highly doubt that the death of his body would stop him coming back if the seal was no longer needed). The way she did, say, Chidori.
I will have to disagree with you, while I agree his actual death scene in the ending was really well done, the aftermath of the party talking about it is completely understandable and I felt it didn't distract from the original ending. Your friend goes to sleep, doesn't wake up, stops breathing and loses his heartbeat, and the doctor doesn't know how they died, they simply stopped. It was a devastating thing for them to experience. The hero got his last happy ending but death is a tragedy for the living. We don't mourn the dead for their sake, mourning is for the sake of the living and that was what The Answer was about, the party mourning over the death of a great person. It would have felt absolutely awkward to have the party be all cherful and upbeat about his death, especially when it came so suddenly and without warning. The way the game handles the groups reaction to his death is largely spot on psychologically speaking.However the biggest issue, is that taking it as a death, I think the actual execution of the death scene was absolutely sublime in Persona 3. The fade to white and peaceful drift to eternal sleep, with dreams of friends floating through the clouds during the credits was absolutely frelling brilliant, and I felt that The Answer's handling of his death really marred that. The battle with Erebus and the reveal of the Great Seal was fantastic (easily the best part of the entire Chapter), but I felt that discussions and explanations of his death after that were just unnecessary, and blighted the overall work. Their content may have been the same, but the presentation was incredibly lacking by comparison.