Spent a decent amount of time saving and running through pretty much every choice in this game. So for anyone interested (spoilers?):
The choice of plant at the start seems to only affect what kind of night terror you have after Date II currently. The peace lily is the safest option, aloe vera is more verbally descriptive, and the spider plant has its own visual.
I've completed 6 different bad endings, noted by their separate titles. There are several chances to receive a safe ending as well, but I think it will only say "you escaped them" regardless of how you go about it.
There's a chance to go get ice cream with Tenebris during Date II, but I can't figure out how I got it the first time so if anyone knows that, please tell me.