I will say this: you can never over build or over think any thing
I don't think our buses flex front to rear (like a banana), now side to rear (torsional they do, regardless of make, if it's a body mounted to a frame it will twist) I have been parked really flexed out, body level and have noticed bedroom door may not close due to gap at latch or be so tight it wont close because door doesn't fit into frame
Now I also have the door mounted at the worst place you could do it, right above the front leaf spring mounts, this is where the most twist is present other than directly between forward rear mount and the rear front spring mount
So I make sure not to have rigid mounts on my panels, they may look rigid, but are made from 5052 alum and have no 90* stiffining...makes sense?
you idea is sound