There's a suprizing number of Medieval wooden castles . Although they tended to be re built for the obvious reason you mentioned.
There's a couple of Russian reconstructions.which tend to look like a Larp version of an American frontier fort.
I'm airing on the side of caution at the moment as this really is the wrong way to go about a project. It'd be a doddle if I could plan it and buy in what was need . But the challenge is to get something useful from what I have . Not what I can buy in.
I'm trying to build something useable and that looks plausible as a castle even though it's fantasy.
So in theory I should end up with a mashup similar to Guedelon Castle ,with Murus Gallicus inspired detailing (which is providing heavy on paint for the base colour.) The main reason for using it as a detail on the face of the walls is to help hide the joints of the modules .Its a sort of belt and braces tactic. As I'm still undecided on whether it should be modular or a static single build.( Work mode keeps nagging single piece display. Gamer head says it'd be more practical in pieces.All my other stuff is but oddly enough this one keeps nagging to be a single piece. For the life of me I can't think why ?

)
It's still down to materials. I'll worry about the end result when I get there.