Do you think there will be a big town that's the size of solitude or white run? Or will it mostly be small villages?

No.

Raven's Rock looks fairly big but I imagine any other settlements will be small villages.

I'm expecting open villages without major seperate-cell settlements like the ones the OP posted, but
there's a good possibility that there will be one, I guess.

I think there's a probability. After 200 years, if none of the Dunmer, specially the Hlaalu, haven't erected a significant town yet, then I would have overestimated their entrepreneurship and proud tradition.

The place where the Telvanni tower is looks quite significant

I'm assuming they will have atleast one major town/city. Remember this is Solstheim and not quite as big as you think it wil be, it is fairly small.