Countries really shouldn’t have extradition treaties with the US considering the US refuses to work with the international criminal court and they’ll have like the worst anti whistle-blower laws combined with some of the worst prisons.
Assange should be charged with whatever crimes he committed in his country not in the US.
It depends on a lot of things. Something self-hosted would just cost the power and Internet you are already paying for but if you’re renting the hosting and maybe even get development for your site it could cost a ton.