No, the host instance will not proliferate your input to other instances. Only your instance will have that and will only share it with other users from your instance.
e.g. I'm on Lemmy.world. I post on the Beehaw gaming community. Only other users from Lemmy.world will see my posts.
Federation can be a one way street. The problem with that is your comments and votes will only be visible from the instance you did it from. Lemmy.world will show other Lemmy.world users your comment but Beehaw will not ever see it, which means your comment will not proliferate to other instances either.
You can still browse content from an instance that has defederated yours but your actions will only be visible on your own instance.
Not typically but it can vary depending on which protocol and which provider you use. Best to check yourself using something like ipleak.net and see if there's any identifying info on there while you're connected.
If you forward a port on your network (or VPN) and point your torrent software towards that port, you are now an "active" node. You can communicate with anyone else, forwarded or not.
If you leave it closed (passive node), you can only communicate with active nodes. With large torrents, this isn't an issue because there's more than enough active nodes to send the data.
Port forwarded: talk to anyone, even closed
Port closed: only talk to port forwarded people and hope that small torrents have someone with a forwarded port.
It'll be general purpose. Mostly Plex but I also host game servers and a bunch of other docker containers on it. I want a good CPU to handle whatever I throw at it.
I think the opposite - it was a dumb move on his part because people now have the weekend to learn about and get used to lemmy. People getting off work and discovering their reddit apps are dead will probably look for alternatives.
Not sure if it's a vanilla thing but if you change the setting to rebuild destroyed stuff, it'll also include the bills when the workstations get rebuilt.
Something like an insect hive will override the workstation blueprint and force you to restart, though.
Corsair is a great choice. You'll have plenty of head room, especially since their PSUs are known to handle higher loads than what they're rated for