OK, you still have options.
I'm 59, my wife just spent a month in the ICU, nearly died a couple of times, 4 surgeries, and many other procedures, just came home from a care center and still has IV's and a feeding tube that I need to help with, she will need more surgeries in about 3 months to put things back to the way they were before. Cost is well past $500,000.00 and will be significantly more before it's all over. So I understand your situation.
Now on to the repair.
There will be no cost in removing the floor and looking at what's in there, if the foam is waterlogged it will be no different whether you know it is or not, still no money involved. Now you may (will) be able to actually see the leaks and touch the rivets and apply a sealer. You won't need much Coat-It, and it's cheaper than Gluvit, I think the small container is $35.00, this would be a permanent fix. Now put the floor back in, it will be no different than not having taken it out and leaving as it was. When your funds are in better shape put in a new floor, or not, the fish don't care.
The best cleaner is waterless hand soap and an abrasive scrubbing pad and or brush, the aluminum cleaner isn't needed and won't do much. You will have removed the stained surface with the abrasive pad.
Now you know the exact condition of all the components, hull, floor and foam, if any of them need more work you can plan for it to be done in the future, but you will be back on the water with a repair that won't need to be done again, and at a lower cost than what you had planned to do.
The last option is to not worry about the slow leak and just go fishing. Zero dollars.