I completely understand you not wanting 3 housecats. Could you put an advertisement in your local paper? Or put up notices at the post office, restaurants, etc. A lot of places here (including the post office) have bulletin boards where people put up notices like that.
My Mom has an indoor cat, and I don't know what I would do with her cat if she were to pass away. I'm hoping, of course, that she outlives the cat.

But if she doesn't, I know that I wouldn't want to bring her to my home. She is a very anti-social cat. She's affectionate with Mom but runs and hides when anyone comes to visit. I already have an indoor cat, so wouldn't want to bring her around my cat either. I would probably ask family first if anyone wanted to take her in, then I would resort to the advertisement in the paper and putting up notices.
Good luck to you, in finding homes for the cats.