Neil,
 
I have to relate my experiences w/stray cats & Ferrets:
 
We had a local stray in our complex who would enter anyone's house.  Very
friendly.  I couldn't stand not knowing, so I invited him in one day.  He
was 4 times the size of Pepper (BEW, a real spitfire).  When she first saw
him, she went up slowly to investigate ( not threatening or anything) The
cat backed away and Pepper moved up.  Again..Faster...Again.  Well that cat
jumped 3 ft straight up on top of the TV to get away from her.  It was so
funny because here is this big 'outdoor' cat who must deal with all kinds of
wildlife (dogs, racoons, etc) scared 'poopless' of a tiny ferret.
 
Second instance: I finally adopted a stray.  I think she was a great
grand-daughter of the one above mentioned. Since then, Pepper had died and
now I have Bandit (Mr. Mellow) The cat was afraid of the ferret, but more
cautious than afraid.  She would always go 'up' to get away from Bandit.
Then she got smart and would dive-bomb Bandit from atop the coffee table or
whatever her roost was, then be gone before he knew what hit him..
 
The SHOULD get along ok.  I wouldn't worry about the ferret though, I'd
worry about the cat.  There must be some ingrown knowledge of each other.
 
One CAUTION: Please have this cat tested for diseases.  The one I adopted,
Kitty, had feline leukemia.  It seems to be the popular malady for cats
these days along with feline aids.  Never heard of either before.  Anyway
after huge Vet bills, I lost her to the Rainbow Bridge.  No, it can't be
transmitted to ferrets, but I had just enough time to get attached to her
before she left.  I'm sure Bandit missed her too.
 
Hope this helps,
 
Donna
[Posted in FML issue 1608]