I would eliminate the Tin Lizzie based on complaints I have seen about tension. If you do a search on the QB for the Tin Lizzie, I think you will bring up quite a few threads that discuss it.
In your situation, I would definitely opt for the Innova with Lightning Stitch. That is my dream machine! For me, the 18" would be enough (can do a 12" block on point). Go to 22" if you think you may want to add computerized quilting. I would never want to do that; I do enough on the computer as it is!