You will need to reposition the surfaces on the new textures. They're completely different layout.
Yes, and I hope the shapes of the panels are compatible. I made them based on what we just had before and used some photos of the original to freely adjust them, so they look almost authentic.
Even the things I made from scratch (do not remember exactly all those parts) have no real measurements
You have to use blueprints for that and it's really hard to get those for military aircraft. There are only a few exceptions like the F-16 Falcon for example, where many guys built a homepit for and you could really get all information you need for that.
If the shape of the texture part (e.g. the main panel) itself does not fit and there is no way to "cheat" them a bit (this is only very restricted possible, or you will totally disort them), we have to make completely new 3D panels. The positions and the scales of the different parts of a texture doesn't matter as long as the shape fits. All other things are adjustable.