Steering this back to T205, I think it's a stretch to combine T207 series with T205 to reach the 400 design number. There are too many holes in that theory for me.
I also don't think the Birds or the Generals or any other non-sport set were the missing designs either. It still remains a possibility and all we can do is speculate, but this is just not the thory I choose to side with
I am sticking with the "unfinished set" theory where they simply didn't complete their original intention.
Perhaps the ATC breakup contributed to this. Maybe the cost of these ornate designs simply caused the new bosses to change their minds.
I don't think it would be too difficult (albeit a bit time consuming) to propose the remaining ~192 players into the set. There are lots of established stars missing from T205, likely dozens of fringe players and practically the entire Eastern League to choose from (less 12). Let's take a crack at it...