My thoughts exactly. This isn't meant to provide structure, just something to mold the leading edges with. You might as well intentionally disolve the foam out after you get the glass on to save weight.
Well, that depends on whether you've built your strakes already or not. If you have, they will have to be adjusted for proper fit and you will have this problem whether you get fiberglass parts or foam parts except that the foam ones will probably be much easier to adjust. If you haven't yet built your strakes, you just build them to match the leading edges.
Yes, I suppose you could probably use it for either the Cozy or LEZ although, I make no claims to have done any testing whatsoever. The Girrrls and I discussed providing parts to make their Cozy IV strake leading edge design available while we were at Osh. It's something we just haven't gotten around to yet and had pretty much forgotten about it until I saw your post today. It's just an idea at this point but I think this is how Randi and Chrissi built their Cozy.