We have a lot of owners on there and there are a bunch of Sprinter owners for for the Plateaus and Ascents. There are getting more and more sprinter owners on there since now more PW models are being built on the Sprinter chassis. With the exception of the chassis itself, there are a lot of commonalities since all the house part is built very similar, so usually how something is done is pretty universal. Like your carpet question. They all pretty much have carpet installed, so how PW does that is a company thing, not a vehicle thing, so if someone took the carpet out in their Excel for instance, it should be the same process you'd need to use.
Anyways, if you do try and take the carpet out, I doubt there's anything but the subfloor underneath. Some manufactures put linoleum everywhere first, then mount the carpet on top of it, but I'm not sure if PW does that. You might consider a call to the factory to ask about how you'd go about doing it.