You really will be spending loads of money to sort the bubbling round the sunroof out. If you remove the grab handles and door apperture seals to pull the rooflining down slightly, you can see the frame itself. It will be rotten. Ford never put any sealing in where the two panels meet to stop condensation getting in.

The bubbling is where the inner frame and the roof panel join together, and the rust is in the frame. You can keep repairing the roof all you want, but unless you actually cut a section of roof out and replace it (which is a nightmare due to the distortion when welding it back together again) it will keep coming back.

The arches are not a problem. You can get replacement pattern ones for about £8 each, and as long as someone fits them properly, i.e. joggle them and weld and seal both sides of the cut it will be fine.

Sorry for the bad news, but I am just being honest. I have actually sold these things because it is almost impossible to remove, and always take the rooflining down @ the edges on any Ford I get before buying it to check.