I keep telling people this, but get him 3v caps.
If the tests you did are all coming up as negative, then its likely that there is no problem and that he is just not getting the proper nutrition. 3V Caps is like a supplement. It will make the fur and skin all shiny by replenishing with...
Maybe let him be indoors and outdoors. See which home he likes better if he's from another home nearby. Maybe someone left and moved away, without the cat.
Holy cow, and hour away?
Hmm doesn't sound like they will adapt well indoors. I doubt they belong to anyone since they hang around the dumpster. I've seen cats like this before at my uncle's house/neighborhood.
Forget what she says. Four cats is not that much really. As long as you take care of them good and take them for regular visits at the vet, then you're in good shape.