People really don't have much time to prepare, so I would advise mixing random and draft elements. For example, each player drafts 1 or 2 Castles, and the rest are chosen randomly (Hvruul can do this), so there's a chance to eliminate a Castle that has changed significantly and for which they haven't had time to practice. A normal hero trade is fine. There won't be immediate complaints about "Moon got picked" or something similar. If you want Moon, pay the price that reflects how much you believe in her.

The city selection has only been improved; all cities have level 2 buildings and 3 stacks each. Having experience in Soda with much worse starting conditions, special preparation isn't necessary; it's more important to have experience with the template, which is individual for each player. It's better to simply add 1 subjective restart to be able to reroll a "disliked city" or an unpleasant setup. I also don't think there's a need for a hero trade, because the heroes should be of the same class, and for example, in Castle, one will take Caitlin, and the other will be left with the dregs.