Oh, right! For the person that runs the bar you can talk to them whenever you're there, you don't have to do anything special to meet them.
For the transformation update, you'll be able to set species options at the same time you would usually input your name. I'll also let you change those options when you upload an older time machine save. And yeah, the species options should change some of the interactions with characters as well as the mirror descriptions.
For the Halloween update I don't think you'll have to worry about losing items, since any items you get aren't particularly important outside of the halloween update. As for losing the green stone, I'm not sure what to do about that other than try to replicate that and try to fix whatever bug happened.