Did you you find flotation under the deck? If you did, put flotation back in. If you didn't, put flotation in.
Rivet mandrels and all kinds of other stuff plug the limber holes. Most of us pressure wash several times until the limbers are clear. Any water will degrade the flotation foam over time, so it's best to make as much of a path as possible to direct water to the bilge.
Your chances of lining up the rivets are about as good as winning $1.6B in the Powerball. If your deck is original with 1 set of rib holes, you still have a lot of meat for new holes. If the deck has been replaced before, not so much AL left. Some of us add what I call rivet plates on top of the rib ends for drilling new rivet holes.
BTW - Your pics are too small.
LOL