I had some more thoughts about the problem... here are my conclusions for the moment:
We'll play 2vs2, with "normal" turn: first team's first player / second team's first player / first team's second player / second team's second player (no shared life, no privat chat, etc.)
With the A option (comparing all creatures of each team to determine the right to pass), a player with a few creatures, whos team-mate has a lot, will be forced to activate all his creatures very soon, and then his team will play only 1/3 of the actions. This seems not good.
With the B1 option (player can pass if he has less creatures than both his opponents), a player with a lot of creatures whos team-mate has very few creatures will be let to play alone for the last actions. This seems not good.
As Lukard expected, the B2 option (player can pass if at least one of his opponent has more creatures) seems to have no big downside.