Would be great if they did not get money from google. They could set.up a donations program or something and regularly ask for it like Wikipedia. Donation based browser, peoples Browser.

In case of Lemmy I used Lemmy-Easy-Deploy script. To host I used Oracle Cloud always free tier. Its risky because I’ve heard people say that since its free they can just pull the plug at any time, so you might consider to upgrade it to paid account, I heard its cheap. About requirements I have no idea. Im running my on a VM instance with Ubuntu minimal 22.04 aarch64. I pushed it to the maximum allowed for free account: 4 ARM cpu with 24Gb of Ram. I dont know anything about hosting mastodon.

I think so, you’d just need to not add any other instances on your instance settings. Not 100% sure. I just started my own instance a couple of days ago. And I could not connect to other communities unless I whitelisted them in settings. Also there’s a bunch of options and variables in configuration files that enable/disable activitypub.