WOW Leslie! First of all, congrats on the possible new addition!

I think going at a VERY slow pace is crucial for introducing most adult cats. Some can go quicker than others, but it'd be safe to start out slow and then quicken the pace if both cats are comfortable.

It always takes Shiloh a really long time to get used to fosters. It always takes her more than a month to warm up to even their scent.

I would keep the cats totally seperated for 2 weeks. Let them smell each other under doors and get used to each other's scents. Rub each one with a towel and put the towels under the other's food bowl. The towel trick works really well.

After a couple weeks, you can slowly introduce them to each other for short periods of time. If Minion is stressed, you could put Fawn back in a bedroom or wherever you'd been keeping her.

When you do eventually let them be together, expect some hissing and growling and fussing. Its perfectly normal. In time, that should go away.

GOOD LUCK