My question to cat owners is: can you test negative to cat allergies,
yet still find yourself in a situation where the cat is causing you
allergy or asthma problems?

I'd say yes. I had a boyfriend with bad allergies and asthma. I got rid of all
carpeting, all drapes, all fabric furniture, put in wood/tile/linoelum,
vertical vinyl blinds, leather/wood furniture. I would light mop instead of
sweep vaccuum so it wouldn't get kicked up in the air. I had three cats. I
wiped them down with moist wash cloth before boyfriend came over. I wouldn't
let them in the bedroom or on the couch where he sat. He was fine for months
until one night he was miserable. The next morning I found cat fur all over the
pillow he slept on. Seems kitty snuck in there. I washed everything and he was
fine again. Another time he was sick again. Then I saw that the cat laid on a
sweater that I had drying then I put the sweater on.

Also, keep your windows shut and use an air purifier. Never open the window.
Wipe down furniture instead of dusting so you don't kick it up. Generally if
people are allergic to one thing, they can also be sensitive to mold, mildew,
dust, dander, pollen...