From a US perspective, what are the prospects of a fair trial for Julian Assange if extradited?

Same as it was for Epstein

the guy is a scapegoat

It will be interesting to see what the US can actually indict him for. He isnt a Citizen or a resident. So treason and all that hype are out. He is more likely to develop a bad case of Epstein Syndrome than anything else.

Zero chance. The UK need to show tremendous restraint and not hand him over.

Almost none. And Pavlov's dogs will all think that's ok.

Zero. Expect him to "commit suicide " any day now.

He and Snowden will be treated fairly...prison has hot food sometimes.

Same as Snowden. Slim to none.