On point 1 - from prior threads you have had a lot of trouble with social dynamics in your group, Elf Witch, though it seems to be more in the group you play rather than GM*. Maybe I've been a bit unlucky with the playing at others' houses, I think it depends a lot on the host. As a teenager I ran occasional games at friends' houses that were fine, but I felt very uncomfortable GMing at a player's house some years ago. But I guess that might have been a particular player with a particular house!
Kicking people out - I think ultimately it has to be the GM's decision, the GM can't GM for someone they don't like or can't stand their play style. But clearly in a group of good friends it can hurt relationships. I had a bad experiences with GMing a home game, where a manipulative player got a kick out of persuading me to boot other players, Lady MacBeth style - and making sure I got all the blame, too. GMing at the D&D Meetup is much better, and generally much easier to manage group membership. If I'm not getting along with a player, there are always other games for them to join. If I decide to quit a game (never actually been booted, myself), there are always other games.
*But your room mate has had lots of trouble GMing her campaign, right? Doesn't the host player cause her difficulty? Maybe if she GM'd at her own place (sans parrot) or in a neutral venue, it would be better.