Looks as if your drums have the threaded holes (6mm or so, I forget the exact size) to allow easy removal from the axle. Find three bolts of the appropriate diameter and pitch. screw them into the threaded hole and tighten to apply pressure. You'll be amazed at how well this system works to remove brake drumss, even those that have been in place for a long time. Speaking of that, considering the trouble you've had so far, I'll bet the brakes will be a real bear to work with.

Went to the garage on New Year's Day afternoon to measure the bolts used for wheel dismounting - they are 8 x 1.25.

Lug bolts are pressed into the axle ends. Sometimes they come out easily if you're lucky. Not sure in your application if there is enough room to remove/replace the bolt without undoing the axle. In any event, be careful of applying too much force, i.e., a big hammer, to the lug bolts as that is an easy way to damage the axle and its bearings.