I feel like Soushi would really REALLY enjoy dressing up as a vampire while trying his hardest not to show it 🤭 He's actually weak to all that black drapery and metallic accents all over him.
Kazuki, I think will probably just dress as whatever's easiest, or something suggested (read: put on him) by Maya and co......like a Lycan!!
((Plus, Kazuki dressing as a lycan complete with a big rough collar to the attire makes for interesting dynamics with a certain person 🤭🤭🤭))
The best present for Kazuki is Soushi’s return to his arms
I...feel like its the opposite in a way actually. Okay this might be a little long and will go into the ramble box because I too have been thinking about this for a while.
I think the best present for Kazuki is finding himself in Soushi's arms again. Kazuki can't live the way he wanted to, and can't die or disappear the way he wanted to, either (because Kurusu and Kouyou stopped him from assimilating into nothingness alongside Soushi), despite wishing to disappear so so badly since the start of his appearance (this was really prominent in 2004 Dead Aggressor).
He thought he will finally disappear like his deepest wish at the end of Exodus, alongside Soushi, carrying the promise they tie between eachother (basically a hardcore kalo lo pergi gw ngikut typa thing), but no, he had to live. For the sake of Soushi at that. He can't even die the way he wanted to, can't even be alongside his Soushi anymore. Of course Soushi fulfilled his promise of meeting Kazuki again, but what is that even for if Ko!Soushi just ends up not being able to even TRUST Kazuki in the first place? Best you can have with the two is them being okay being put in the same room.
And in the end, Kazuki became basically eternal after being festumified to an Element. He will continue to exist even after everyone he knows has passed. Forever. And forever is a really long time.
So yes, TLDR I think its a little uhh the other way around. The best ending Kazuki can have for himself is to be in Soushi's arms again. To be alongside him. Even in nothingness, it wouldn't matter because he is with Soushi...