Abandoned kitten, worried bout my currently cat..?

i posted a question some time ago but i honestly had big issues replying. i will try and make the question short but ill give details so that everyone can understand whats going on. i currently have a persian cat and i fell inlove with a homeless cat that was up to adoption on a vet i used to go, to make the story short im not currently with him at the moment because lots of things happened with the cat and the vet had to keep him ( snap negative but the cat had neurological problems after neutering, i wanted to keep him but vet said she would because he needs special care.) i was really sad because of everything that happened and i decided to look for another homeless kitten in an adoption place. i went to 3 different places and i wasnt able to decide, i went to a petstore that i know sometimes has cats you can adopt and a woman came and ask for a vet and she told me she found an abandoned kitten that apparently the mother rejected and they heard her crying for 5 days and they just didnt knew where the crying came from. the vet checked her said she was fine but needed food ASAP and lots of care. the woman told me if i wanted to keep her because she couldnt due to the fact that she had a 1 year old baby she was taking care of (she was holding the baby) and i accepted. the kitten was SO SMALL her eyes were sticky and couldnt open them and she was smelly and thin ( the kitten was 2 weeks old atm) its been 2 weeks and with alot of dedication,and sleepless nights shes now a totally different kitten. shes so beautiful, chubby, super healthy, affective and she has grown so much i love her!! (been feeding her KMR and shes dewormed) i have her in a quarantine" room with alot of stuffed toys a bed and shes super comfy because the vet told me ( i took her to a vet that specialized in homeless kittens) i need to keep her distant from my current cat till she gets the snap test done to her. she said she doubt the kitten is sick because she has developed perfectly fine im very worried because i want her to be ok and keep her, but im also worried about my cat. my question is, is it ok to have her apart from my current cat and how old does she need to get the SNAP TEST done? any extra advice would be appareciated and thanks everyone.!