Thank you all so much for your replies!
Unfortunately, I can’t seem to get any of the resizing data to translate to FCP via XML or into Resolve via AAF.
When I import the sequence into FCP7, the unsized clips have a scale property of 100, and any resized clips have a scale property of 0, but their center point is adjusted.
I feel like this started because I started by right clicking on the clips in PrP and choosing “Scale to fit Frame”, which, unlike FCP, doesn’t adjust the scale size in the clip properties, so there is nothing to translate over.
In fact, I don’t see any property that choosing Scale to fit Frame in PrP changes, except for the fact that it resizes to fit the frame.