Probably won't happen. [ He can only say "probably" since there could be one or two reasons that would drive him out of human populated areas. ]

Guess this place is full of opportunity to meet all kinds of people. [ Nico can't blame him for not being all that spiritual and needing time to realize there are deities out there. ] Yes, and yes. Dionysus' wife used to be mortal, and even though demigods half-godly, we could become one too. Gods becoming mortal isn't something that often happens, and is usually a punishment. I think it's mostly temporary, too. Our sun god spent about half a year as a mortal and had just gotten his godly status back.