Java edition is easy to selfhost, did it as a docker stack a while ago. Apart from that, it really depends on what addons etc. your players are usually playing. Most things can be done with not too much effort, but that’s probably the thing you need to find out.

You’ll still be on the hook for US taxes.

Don’t use external drives as non-temporary storage. Backups etc, fine, but not as a replacement for internal storage. It will only lead to headaches at some point. Especially as you have one extra slot.

exact

No one is able to tell you that. Hell, no one can really predict the general direction things are going.