Definitely sounds like inbreeding for sure. Which is where you will usually see the the blindness/deaf come from. As well as the general sickness.
Sneezing/Breathing problems are typically respiratory infections. Common in cats.
But seriously, the cats being stray/inbreeding. Anything and everything can be wrong with them. You say the ASPCA won't do anything.. But is there just a regular animal shelter around?
I'd put them in a box or something and leave at the front door for either the ASPCA or Animal Shelter. Especially if they are refusing to do their jobs to begin with.