attaching garage to house via breezeway - movement concerns

Okay, - here's the situation; I may need to make my detached garage an attached garage by building a breezeway. This may be the best route for getting a build permit which I've decided is a must. FYI - I've been documenting my build here; viewtopic.php?f=2&t=11485 The two potential options are 1) an unenclosed (roof only) design or 2) a fully enclosed (with poured foundation) design. I've attached to images for reference. The concerns are relating to the garage shifting or 'floating' and putting pressure on the house, possibly causing damage. The questions: If I went with the roof only design should I worry about the garage 'floating' enough to push or pull the breezeway structure away from or into the house (which is a bungalow with full basement foundation)? The garage was built about 8 years ago with a permit by the previous home owner. The town only keeps records for 7 years and may not be able to pull the original designs in order to find out whether the foundation is a simple floating slab on grade or whether there were footings put in below it as well. So I don't know about that yet. If I went with the fully enclosed option and poured a foundation in between the garage and the house would I tie that new foundation into both the house and garage foundation via expansion joints? Could I not tie the new foundation into the house at all (keeping i decoupled)? Any thoughts/recommendations from those in the know are much appreciated!