So I went with your suggestion, kind of. I only have 2 jackstands so I just lifted the drivers side of the car up so both front and rear wheels were off the ground, tried to calibrate but still failed, same issue. It wasn't until I put the car back on the ground that it then went ahead and did its calibration. I did this with Forscan as its a nicer UI to work with. I may need to do it again though as at the time I didn't do any manual calibrations as it says, so I think they're off a bit again. I would say that is a confirm "Fix" for it, not tempted to take the battery out again to confirm it's not a fluke tho! 😂
I also had the same issue with switching from pre-facelift to facelift.
Might be that as you said, with the battery being disconnected the system needed to see the full travel before being happy with the sensor positions.
I've read a few boards on here and it seems I'm doing something you've already done. I want to convert my 2 electric windows into full global with power mirrors, so just now need to find a cabin floor loom from a 09-10 that has the wiring (not easy to come by these days I've found!). Also tempted see about getting dual climate as well (as I have the dash loom), totally not likely to be worth the effort, and probably WAY too expensive to justify, but it should be fun... ha.