Ralph,
On the issue of an ‘exchange’ in 6-player football, if you haven’t already, define the Team A player that first possesses the ball after it leaves the snapper’s hand(s) as the “receiver of the snap.” That could be the player intended to receive the snap, or any other Team A player who is the first Team A layer to gain possession of the ball after it leaves the snapper’s hand(s). After that, the receiver of the snap must pass the ball (forward or backward), hand the ball, fumble the ball, or kick the ball before it may be advanced beyond the neutral zone by Team A.
In your game, what happens if the ball does get advanced without an exchange? Does the ball remain alive? Foul? Enforcement spot?
The issue that you also need to address (which Texas has not yet formally addressed) is what happens if the loose ball should happen to travel beyond the neutral zone before the exchange has been completed? Does that count as an ‘advance’? And, if it then returns behind the NZ (still before an exchange has been completed)? If A Team A player recovers the ball in/behind the NZ, does that count as an exchange?
You should clarify those things.