As you can see everybody has ideas on how to fix it. You have to trust the person doing the work to blend the ideas.
My thought...Kevlar good on the inside doesn't sand well so it's good for an inner wet lay-up. Coremat I've used it for bulk and some stiffness no strength. Foam use boat build quality nothing else. Wood - never.

Good luck


Mike Shappell
www.themanshed.com
TMS-20 Builder
G-Cat 5.7 - Current Boat
NACRA 5.2 - early 70's