I talked to Cruiser Outfitters and SOR over the phone and they both said that they couldn't source them anymore because Toyota stopped making them. toyotapartsdeal also doesn't have them anymore, but, I haven't called Toyota, I will give that a try just in case.Is the air pump belt not available from Toyota? I got mine from there not so long ago.
I actually have seen you post in other threads about running the vent hose up the firewall and I've seen the instructions on how to do it, I will give it a try! It just seemed like folks usually go for the hose-on-the-filler plugs approach most of the time.The real reason your transmission is overfilled is that the transfer case vent cap is glued shut (due to 90wt. on the rubber disk) and when the xfer case heats and the oil and air expands, it pushes the 90wt. through the weak/old seal and into your transmission, which is vented through the shift tower.
If you don't immediately want to pull your trans and xfer and replace this seal (who does?), then at least pry off the OEM vent cap on the transfer case (not super convenient to get to) and push on a piece of 3/8" fuel line as a vent hose, and run that hose up the firewall. This has fixed this problem for me on several FJ40s. I used a hose clamp to attach the 3/8" fuel line to the stub of the vent assembly and it is secure.
This has been documented extensively on Mud. I would argue that the hose-on-the-filler plugs is a bit of a hack and costs a lot more.
As for your stuck x-fer case drain plug, but sure to use only a 6 pt. socket on it, and an impact gun's 'rattle' might just what it needs to pop loose.