Lol oh I don't need to read your post again. You want a trans woman to come fuck your husband but not touch his penis, go down on him, or receive penetration themself. This sounds extremely rigid and demeaning of the third person. They are not objects and come with their own desires and boundaries. I have had many threesomes and I'm telling you these are conditions that are highly unlikely to yield someone who wants to be objectified so rigidly by both of you (you might find someone but highly unlikely)

If you aren't ready to have his penis touched, you don't sound ready to invite a third person. If he's already making jokes that he's going to throw the boundaries out the window and do what he wants during the threesome, then he doesn't sound like he's ready to invite a third person.

Maybe you should hire a sex worker to meet your specific needs.