Clean the grease off and start with the swing arm spindle, easier to deal with, with it still held in the frame. Use a length of 1/2 UNF stud bar, nuts, washers and suitable spacers to pull the spindle out of the arm/cradle. You may have to use a 1/2 UNF tap to clean the thread in the spindle to allow the stud bar to screw in.
Now to the iso stud, is the long iso stud removed? The photo just shows a tube? I would cut the rubber gaiters off and saw through the iso end caps, easiest done with a thin cut off wheel in a angle grinder. That gets the cradle out the frame without damaging them. The cost of replacing the iso rubber, end caps and spindle is nothing compared to repairing bent frame plates etc that can happen when hammering seized/rusted things trying to get them out. One thing that experience gives you is knowing when to sacrifice some bits to save other stuff.
You are going to have to get busy with a welder, looking at the photo again there are holes in the frame tubes putting a question mark over the frames integrity