According to your pics , the "split" that appears to be on top of the frame, by the A/C, could be repaired, depending upon the wall thickness of the area that is to be welded .
Pic # 37 on the other hand appears to be a major problem . It looks like that pc is beyond repair , w/the exception of cutting that section out & replacing it . When the metal flakes as shown in the pic , it is impossible to weld to .
If I was going to restore the car , I would put another frame under it .
It just seems to be to much going on with the frame to try to salvage it . 55mole