In the big picture, removing the baby teeth should be done, but replaced with implants or, at the very least, bridgework. Moving premolars to the canine position would be terrible, as the effects on your facial structure would be very bad. Braces should be used to maintain or correct the space for the implants and preserve the bite.
If narrowing or constriction of the arch form can be avoided, it should be. Invisalign can tip teeth well, but brackets are more efficient with moving roots. Overjet is often corrected with elastics, and brackets are easier to use with this. If elastics are used, then the orthodontic process is no longer invisible and use of Invisalign can be questioned. Hygiene becomes the only benefit to Invisalign at that point.
