Your mud just gives me the opportunity to toss a little more mud into the water and stir it up
The three points rule for establishing FC status clearly does not apply (and I think you already knew that). Ball is not being dribbled, and 3 points rule applies to player dribling ball. If a loose ball or passed ball touches FC on one bounce, it is FC. If a player is going from BC to FC, steps into FC with lead foot and lifts back foot, the player is FC. So A2 having one foot on court and that foot is FC would have been enough to establish A2 as FC. A@ subsequently touching ball without ever touching BC again would make the ball FC.
If you couldn't see it and your partner didn't know the rule, oh well. You aren't going to get into this kind of discussion during the game. And since we will never know where A2 was, it will remain a mystery as to whether you got lucky and got the call right. Regardless, partner's reasoning on 3 points being required for FC status was wrong, and your reasoning on team control was also wrong.