I don't see why you couldn't leave the cabin interior unfinished. I'd want the hull , stringers, cabin sole to be epoxy encapsulated, but I don't see any need to put anything at all on the berths, cuddy sides, or ceiling other than for looks. I think if I were to cover the interior (meaning interior of the cuddy cabin ) at all I'd use a val spar polyurethane and be done with it. just my opinion.
So is there something I'm missing ? Is there some structural need to have the cabin ceiling epoxied and painted ?
If the interior walls of the cabin have some structural need to be epoxy coated and painted, then so be it.
I doubt that that is the case, but it wouldn't be the first time I was incorrect.
BTW, Joe Nelson can sure stir a pot !