one had the rudder connection ripped off; one had the boot dislocated (boot might be the wrong word, it is the bottom of the four posts that go into the hulls and I believe is cemented or glassed to the bottom of the hull)
Are you taking about Hobie 16? Wave and Getaway are more popular rentals. There is a big difference in hull repairability between fiberglass (H16, H17, H18) and rotomolded (Wave and Getaway) cats.
I would also check condition of the sails and comtip for UV damage. If the boat was left with the mast up 24/7 in full sun, I would expect a lot of comptip live already gone.
one had the rudder connection ripped off; one had the boot dislocated
Some picture would be helpful.
Your best bet is to be patient and picky. Finding a boat in really good condition that has been stored under a cover or indoors is the best way to go.