Hi Bill,,,,
I have a .22 Talon (18 inch barrel) and a .22 condor. Both of my rifles run on HPA and I've never shot them on C02 (even though I have a C02 adaptor that came free with my Condor) so I can't answer your questions concerning the CO2, but I can answer a couple of your questions.
#5) The SS and the Condor frames are longer than the Talon.
#6) I have a Leapers 4x16x50 on my Condor and it works great, I love it. As for the mounts, yes, you will need the high mounts,,, matter of fact I would suggest you go a step further and order the Air Force "Tri-rail" , install that AND still use high mounts. I have high mounts on my Talon and it works for me, but on my Condor I installed the Tri-Rail and the high mounts and it works so much better that I'm going to be ordering a Tri-Rail for my Talon and remount the scope.
Regarding hunting with C02....... like I said I've never used it on my Air Force guns,, not yet anyway, but I've read plenty of posts on the Talon Airgun Forum where guys routinely take squirrels with C02 powered Talons, SS's and Condors.
Now that I have my Condor for hunting I'm thinking of using the free C02 adaptor I got and setting my Talon up for C02 this summer and using it for my starling hunting at the duck farm I pest shoot at. I'm probably going to order a .177 18 inch barrel to use for the birds.
Well, I hope I helped you a little. I'm sure one of the other members who know the answers to the rest of your questions will chime in soon.
Jeff