Lots of shaking getting worse, could it be tiny vac leak?

Hey folks! I have a 1982 Rabbit Convertible that has been running well but has always been a bit 'shaky.' Recently it got MUCH worse and I'm worried it's going to rattle itself apart. I'm also getting around 23-24 MPG and definitely losing power. Here's what I've done/replaced so far:

- Fuel system is all pretty much new, gas tank to injectors
- New motor mounts & engine aligned
- New plugs, wires, distributor cap and rotor
- Idle speed adjusted
- Static timing set after motor mounts replaced
- Timing set with a timing light
- Fixed hole in exhaust pipe right before muffler
- New idle set screw o-ring
- Checked for vacuum leaks everywhere, only found one small one:

I found a very small vacuum leak in the throttle body. When I spray it with carb cleaner around the shafts of the butterfly valves, it revs up a little bit. I took it off , sealed the ends, poured soapy water all over it, and then blew into the vacuum hose port. It bubbles up a little bit around both of the shafts, top and bottom. I attached pictures here.

I would appreciate any input on this, but here are my specific questions:

1. Is there any way to repair this? It seems like you can't get the shafts out because the brass flaps are swaged to them. I can't find throttle bodies for sale anywhere online either!

2. Can you think of anything else you'd try to get rid of the rough running?

I have two more issues that I'm including because they may be related:

1. When I first start the car cold, it dies right after a few seconds unless I give it gas. I have to keep it at 2k RPM for about 30s or more. (probably WUR or cold start valve? least worried about this one)
2. When I try to start it warm, it takes 20-30s of constant cranking to get it to start.


Please let me know if you have any ideas, thank you!