This may not make things more clear, but it's a voice of experience. Pinot was very sick (as most have read, I think) at the shelter when we got her. She had some unnamed respiratory virus that almost killed her. We knew she needed us, BUT we have no other kitties at home! We have a situation where we've been told NOT to get any more due to her status as a probable carrier of the disease. You are in a different situation; there are others to consider.

Speak with your vet, have the kitty checked out, and get clearance first. That's my best advice. Thank you for taking the chance, as those kitties need all the help they can get - good luck!!