... I feel getting the floor stiffer is important for long term.
I just would like to make sure people understand that the starboard side floor area seems to have the foam loose/ broken/ pulled away. As compared to the port side where the Luran is just no longer glued to the foam.
I am curious if I should get some empty caulking tubes. Fill them with gorilla glue and inject that into the hole in the floor. Maybe have holes near by and fill until it comes out surrounding holes then weigh down with flat item and weights.
Loose broken & pulled away foam is something that I haven't seen before. That may need some additional consideration.
I used smaller holes that were closer together when I glued down the delaminated portion of my floor. My method was the same as you describe. My results were good.
Honestly I look at the boat as very usable as is with mostly cosmetic issues from the cracks. I can slowly do repairs as I figure out the better ways. This is a very doable project with the goal of a few years of learning how to sail and see if we like it.
In the beginning, I got a roll of white duct tape & just taped over the cracks to keep water out while I tested the boat. I later went back & did proper repairs. I take mine out in the ocean, so I needed to do reliable repairs. If the boat seems structurally sound & you are not going out further than you can swim, then using it as is for now may be your most cost effective option, both in time & money.
If you do have a serious failure, I would probably buy the standing rigging, deck hardware & sails off of you for the price you paid for the whole thing.