That precious baby has called to you since you saw it. I have a feeling destiny may be at work here.
I think sometimes the kitties will surprise you with the way they handle things. They never do what we expect them too! Maybe if you kept the little one in the bathroom for a few days so Mishka can get used to the idea. Give them short visits and see what happens. Very rarely are there two cats that can't live in the same household. They always work things out and usually end up being friends. This kitty is still a kitten and that is the best time to try this. I wouldn't try an older cat if Mishka is that jealous. Just make sure he gets lots of attention and share in the play time and I think he will surprise you. Mishka just might like having a brother/sister!