I actually got excited when I first saw this Bridge XP, and if it would work - depending on how their methods are - our bridge wouldn’t be a whole lot different. I tried to use it for Algorand and Polygon though and only got as far as this - and this wallet is full of NFTs. So I am not sure if it works.
Regarding royalties, I’d refer you to my response to Stitch. It depends on how the marketplace deals with it. Baked in royalties that tie to the creator address are not carried over. I can ask the devs to think about it, but I don’t really see a way of dealing with that at first thought.
How collections / creators are handled I don’t entirely know what you’re referring to. Do you mean like how a multi chain collection is registered and showcased on a marketplace of some sort? My simple response would be that it depends on the methods and process of registration of collections of said marketplace.