Secondly, did Snorri believe Odin was a man?
Almost certainly he did. Assuming he was an educated man, and not some semi-literate nutcase.
The whole idea that our ancestors disguised their true beliefs to avoid being executed for heresy is a bunch of overblown 18th and 19th century romanticism that has caught the public imagination and won't let go.
These were educated people, taught in church schools. They were up to date with the science of their day. They knew Odin couldn't have been a god, although if they were a bit on the superstitious side they might still have made little offerings to the house spirits "for luck". (As I do!)
The only avenue open to them to understand the old myths was to adopt one of two popular strategies. Either, the old gods were demons who led the people astray, or they were humans who had become gods. Different writers adopted one theory or the other. It's noticeable that the worldly and sophisticated people mostly went for the idea their ancestors were just humans, but still worthy of respect, while the rabid priests are the ones who thought the old gods were demons.
And, they knew if Odin was human he must be descended from Adam. How could he not be, if that's what the latest and most sophisticated histories were saying?
The death knell for the old indigenous history was that their tales were oral and went back only a bare number of generations, while the Roman world had written histories that were thousands of years old.
You're going to feel pretty foolish if your guy created the world maybe 800 years ago but the other side has written records going back 5000 years.