I can answer a few of your questions:
1. Just find out what I have here (grey interior?)
Majestic badged drums are manufactured by Star, my guess is early 70s. I have a blue sparkle 16" floor tom (no badge, Star brand) with a grey interior much like your bass drum. I've paired it with a 60s Star kit, all of which have reinforcement rings, but the FT doesn't have them.
5. should I put felt in the lugs? does it go around the spring completely or just between the spring and the shell?
I recommend putting felt in the lugs, yes. I didn't when I restored my kit, and the springs buzz all the time. I'll eventually get around to removing the lugs and stuffing them with felt, and I'll probably surround the spring with it to be sure to eliminate any buzz. Right now I typically practice with IEMs so I don't hear the buzz that much.
6. Is it reasonable to think I might find a matching tom?
Red sparkle isn't too rare, and neither is that lug type, so yes I think it's reasonable you'll find another. I wouldn't be too concerned about finding a drum with a matching badge, however.
7. Does the pedal hold up the back of the drum or should I get a small riser? Seems like clamping the pedal to this rim is asking for trouble.
I have a new Rogers Dyna-matic pedal and it clamps to that same type of hoop just fine.
8. Which heads do you recommend? Ported?
I have an Evans EQ4 batter with a non-ported Remo Fiberskyn resonant head on my 22". It sounds great. I'd be open to try other similar batter heads, including the EMAD series.
9. The hoops have a very deep groove in the center (ha, at least the hoops have groove!). Is this for anything other than collecting grunge and rust and frustrating restorers?
Nope, not that I can tell, lol. I soaked mine in Dawn/water and it seems like all the rust and grime was removed everywhere but in those grooves. I've thought about getting some chrome ribbon or contact paper and cutting it into thin strips to stick inside them.