Like you said, Koizumi wasn't someone he really had time to get to know before his death, but before her death he vaguely thought she seemed useful in trials (you know, from the popcorn seat), probably more so than most of the people there. He kind of missed her arrival too since he was helping Kuzuryuu with Dipper, but when he finally did get to meet her it was when she was being pretty gung-ho about his silly game that he was doing to make himself and everyone else feel better, so that made an excellent first meeting! And after being stuck alone with the grump squad he really appreciated just being able to have some fun.

Personality-wise, she actually reminds him a fair bit of one of his close friends from home, so he was pretty comfortable hanging out with her right away. The fact that she started doing the same thing and trying to come up with more fun stuff for everyone to do gained her points in his book as well. Umm, this small moment was actually pretty touching to him though - he spent a lot of the beginning of his graveyard stay privately beating himself up for being so useless, so he honestly expected to not get much support when he volunteered to go. Instead, she said she'd count on him and even reassured him she'd still keep people's spirits up so :') A bit of dokis there I must say!! Then once he got back they had important brainstorming, made an eye searing flag and all that good stuff. Maybe it didn't amount to much, but they were a pretty good team. So in general, his feelings toward her were positive and pretty uncomplicated, so even if they both kind of stuck to the ol' stepford smiler guns, it seems like they could understand each other fairly well despite that. They have the potential to be really good friends, and ... he really hopes whoever picked her up at the endgame did not take her back to the same place she was before and that no one will try to hurt her again!! ( If not, girl, get in the You Show van and we will set you up with some photography themed cards :|;;; )