So I had a change of plans (again)
After re-re-packing, I ended up putting my "other" shoes in the bag. They were much lower cut, and they fit when I placed them at the bottom of the bag. I'm now going to wear the shoes that I haven't broken in yet, but that won't be a big deal because I can just take them off when I get on the plane, and if I have to, I can change them when I land. So now I'm back to the garment bag again
Everything fits well, in fact, I have even more room available than I did in my roll-on. I even took pictures... The garment bag is very nice, I just found that it also has a "slot" in the fabric through which you slide the handle of the rolling luggage. I measured everything, and the thickness now ends up @ ~22.5x14x~9.5 (it can squish to 8"). So I'm guaranteed to fit in the overhead and sizers. Yay
We'll see how this all works out when I get back... Now it's off to the airport with the garment bag.