Seems like a reasonable position? If your goal is a safe welcoming community, cutting users who do not fit that initiative makes sense. If someone is racist or insulting, regardless of if they have donated or you see an influx of people with similar ideals, it is against the goals and objectives of the instance and the community they wish to foster. So, cutting them off seems appropriate.

Yes.

I think Jisti does all of those things. Essentially a self hostable zoom. Audio, video, screensharing and text chats.