Maggie May and Mazie Grace are gradually becoming more used to each other. Mazie Grace tends to ignore Maggie May, and Maggie May keeps her eye on Mazie Grace the whole time she is in the house.
We've been letting Mazie Grace in several times a day. At first we closely supervised the two cats. I did not want them to start off by fighting, because I was afraid they would never be friends if they did. I think Maggie May was afraid of Mazie Grace, she definitely did not trust her. This is the first time Maggie May has even seen another cat since she was just a tiny kitten..
We would let Mazie Grace stay inside until the hissing started, then we would put her out. So far, we have not had any fights and we are not having to supervise as closely. Each day they seem to get a little more comfortable around each other.
Hopefully one day they will become friends and will learn to play with each other. Mazie Grace is not a house cat, she does not particularly like being inside. She has not learned the rules of being inside, such as "don't jump up on tables, etc.". I guess it all will take time.