1. hulls should be able to hold the weight of a person, the can take a hard push once in a while(don't actually stand on them, it will make them delaminate in the future)
2. Correct, they should be rock hard.
3. I think you're safe as long as you aren't pushing with a hammer.
4. not really, pressing with your hands is as good as it gets, without slicing open the hulls.
5. you should look at/press down on the sides of the hulls as well as the top, along the entire length.
6. look for small cracks and also deformations along the hull. Any spot that doesn't look right or follow the lines of the boat could be bad, or it could just be a past repair)
Good luck, let us know how it goes.
'79 H16 "Carmelita"