Drill bits and a drill press are the "special tools" you need to remove those parts. New rivets and a rivet press as well as new spacers or drill them out and lay them in place. The screws will hold everything together.

I was just about to start a thread asking about this. Spacers & drills huh? Hmm. Okay.

How does one carefully rivet said parts into the plastic without going too far and snapping it from the squeeze?

Also, any parts links to Marco, etc for the spacers?

Rivet presses can be a tad expensive for a one-time use. You can also use small nuts & bolts, though it won't be original. There are also kits you can use without a press. Mileage may vary.

For the metal bell housings use a small thin soldering iron place it inside the metal bell warm for 3 seconds and wiggle it out. Then while the bell is still on the iron line it up with the hole on the new plastic and hold for 2-3 seconds till it pops into the hole and as soon as it does remove the iron and sit it flush on a flat surface. The plastic will reform around the hole holding it in place. As for the rivets I drill them out from the back and use a small screw with a nut to replace.

Okay, that sounds doable. But normally doesn't metal expand when heated? Wouldn't I want the opposite(shrinkage) effect? I know with the 3 bells I can rotate them somewhat.

I might keep the bell-attached pieces in place since they look pretty darn decent as-is and keep the new ones for spares.

I have used this process of 17 different full restorations and never had any problems. It works but I
think your reading too much into it. As long as you keep the heat to a short time you won't have any issues. If you want to test it drill a couple of holes in the old plastic and do a couple of test runs prior to doing it on the new plastic.

Plastic will soften long before metal will expand. If you get it hot enough to expand the metal the plastic will be junk.