I really don't know about changing the drums. I'm sure you'd have to get the same diam. and width for the shoes. I used a 57 Pontiac rear end and it used the same shoes and cyl as my 81 chevy pickup, just didn't have self adjuster. If the late model drums will fix the hubs, you could turn them where the hole had a new surface and drill to match, then the drum would cover the old holes in the hubs. I think I'd put some kind of sealant on the drum to hub to help seal them.
If I were you, I think I'd be compiling a things to do list.