who you talk to

In my house, no. It's only a big deal if the president or other officer comes up and temporarily joins your conversation.
You do not get a blank slate everyday at all. But that does not mean you should stop trying if you feel like you messed up a round. A lot of girls change completely between rounds 1 and 2 because they got seriously cut from a lot of places and are more serious. I talked to a girl I absolutely loved during Display, but a sister who talked to did not vibe well with her (I honestly do not know why they were matched). I made sure to make it clear that I wanted her back for sisterhood. I know I talked to someone yesterday who was a snooze that another sister talked to on display and fell in love with. These things happen. Not every match is perfect, but try your best every round.

Bump how do the houses where everyone votes do their list?

Another note is that VPs/officers are often juniors and seniors and bump groups are often assigned/matched based on the sophomores. So if they match you with a sophomore they think you'll get along with well, and the Philanthropy chair happens to be in her bump group, it could just be a coincidence.