OK. Items I want on a turntable are an isolating suspension, vacuum clamping, a magnetic thrust bearing and a versatile arm I can adjust to the majority of cartridges. In terms of clamping, reflex clamping is a second best and a good standard thrust bearing is tolerable. The other traits can not be compromised.
The Air Force Three is a complicated used turntable with a second rate arm. I would not even look at it. The Firebird and Kuzma R do not have suspensions so you would have to spend an additional $5K on a MinusK platform.
The Ref 2 and SME 20 are very similar tables. Both have a suspension and both utilize reflex clamping. The Safir regardless of anything anybody including Frank Kuzma says is viable for very low compliance cartridges only. It is otherwise well designed. If you are going to spend the rest of your like with a Koetsu, fine. Otherwise you need to look elsewhere. The Reed 2G, Tri Planar, 4 Point 9, SME V and Schroder CB are all excellent arms. I went with the Schroder as did Mark Dohmann. He demonstrates his Helix turntables with a CB.
Of your selections I would get the SME and put a Schroder CB on it. My next choice would be a 4 Point 9. The Safir is Frank Kuzma doing his "just because I can" act.
A Sota Cosmos offers Vacuum clamping, a great suspension, a magnetic thrust bearing and the CB fits perfectly. On top of this you get state of the art speed control and a great isolated hinged dust cover you can use during play. Just an FYI