Rebuilding 16' 1977 Invader

A couple of questions for anyone that wants to take a stab at this.

Got a cheap project boat and decided to tackle my first Fiberglass boat rebuild. The boat is 16 foot trihull outboard invader. Total rot in every piece of wood in the boat. Floor turned into dirt, stringers rotten out broken into pieces when dried out.

Here is wher I am at. I have been doing alot of reading and have a pretty good handle on things. Removed all wood/compost and foam from boat Stringers removed ground down to bottom. Trailer held boat pretty well so decided to remove and replace transom while I was here. Middle was rotten through.

New transom is in, Stringers are in, getting ready to put the floor in.

Here is my question. It looks like the floor was floating along the side of the boat on top of the foam. Does that sound correct? Do I lay the floor in place and pour the foam in and let it fill all voids and that will support it then glass the top of the floor in. Or do I tab the Sole supports some how with chopped Fiberglass or such to hold them up. Looks like when I pulled it out it was just laying on the hull and glass over top. Want to do it right, not neccessarily like it was done originally.

Another issue I am not sure about. After floor is in place there are 2 vertical supports 4x12 inches on both sides fore and aft that are glassed in with Horizontal spacers 4 inches wide. Think it was to attach inner wall to. Do you think that is structural or just to facilitate attaching inner wall to. I was thinking of modifying it more to my needs.

Last question while out getting the sole material had a freak rain storm that filled the boat. Yes it was out in the clear blue sun but all glassed and cured. Drained well as it should now that it is rebuilt mostly, but I noticed that in the motorwell near the drain is some sticky goo that looks like glue and appears to have eaten some of my cured epoxy? Any ideas as to what this is. All glass was cured for several days everything hard and dry in there. This has appeared right around the drain hole that was just drilled out that day. I had not yet sealed the hole properly. Could that be Glue from the wood or some reaction to something. I used Exterior Fir super Ply for the transom. It dried out fine and I ground out and epoxied over everything back there again. Just kind of concerned about that.