Last night I started cutting out the soft wood in the right wing leading edge.  There was a mouse in there at some point. No nest but some shreds of foam, a few acorns, and other leftovers. I kept cutting until I was back to clean wood and couldn't feel or see significant damage in the past the next rib.

Bud Brown added 2 false ribs between each actual rib to help hold the profile. It seems to have worked well.  The plywood skin is 1.5mm and there were places where there was at least another .5 mm of filler.