Question regarding URIs - how to tell they have cleared up for sure?

I have been considering adopting another kitty to add to the family, so much so that i filled out the application for one at the local shelter. I was encouraged to come in and see her yesterday, and found out she's recovering from a URI right now (she's on medication for the next for days still). They won't let anyone take her of course until it's completely gone, but it sounds like she's had it pretty bad for awhile. Mostly with sneezing from what I was told.

I get that URIs in shelters are as common as colds in kindergarten. And can go back and forth so much, it seems they never go away. I'm curious how does one know for sure that it has cleared up though? I have four kitties at home, and obviously don't want them to get sick. My Sara is on an antibiotic at the moment, albeit for an infected tooth and abscessed anal gland. So don't want to add something else to the mix.

And yes, I'm crazy for adopting another cat. I am sure some folks feel that way anyway. I lost my Lucky two and a half weeks ago and have been trying to honor his memory is the best ways I can (donating to local shelters, etc). Then I decided the ultimate way I could honor him would be to share my love with another kitty and giving it a forever home. 

Gosh, I'm so sorry about Lucky, but how wonderful of you to want to give another furbaby a home to honor him   She'll be lucky to have you.

As far as how to know when her URI is all cleared up, I honestly don't know, because as long as she's there in the shelter, I think she could just keep being exposed, and it's a cycle that could continue, so she could appear to be symptom free, yet it could possible be brewing up inside her again, couldn't it?  Maybe you could ask your OWN Vet is that's possible and see what he advises?

Of course, you would keep the newbie in isolation for awhile anyway, to begin introduction, so if she starts acting sick again, you can just treat her while in isolation in your home before your kits get exposed?  It'd be trickly, bit doable, I'm guessing. 

I will say isolating in my house is a bit difficult. When I got the 8-week kittens in July, I was told to isolate them. The only place I could do that was the bathroom (too many kitties call my bedroom they own). And they snuck out in the small space between the door in the floor, little buggers. So, there went any idea of isolation.

She obviously couldn't sneak out though, being three years old. Plus, it's literally the warmest part of my house right now, so she might like that.

One thing I like about this shelter is I get a free vet visit (assuming at the vet they use next door to it) within two weeks of adoption. I'll definitely be making use of that. I will talk to my vet about it also though, thank you. I think he will mention isolation as well for sure.

I can say this is my very first time ever adopting from a shelter. I never needed to go to one before, cats always seemed to find me. And while there have been a couple people I know looking for homes for kittens, I didn't really want another kitten. Plus I know they have good homes until they find a forever home. Two kittens was enough for awhile. Mine are six months old, and instead of being teeny tornadoes, they are bigger tornadoes, lol.