I went with Heidi, she seemed really interesting to me! I played Parsnip before playing through this game (actually only found out about this one through it!) and while I don't think it's necessary to enjoy this story, it definitely provides better context, and I got a lot out of having played it.
Honestly, the other characters having routes kinda slipped my mind with how engaged I was with my playthrough :P Definitely gonna spend some more time playing later though, I wonder how different I can get this next playthrough to be?