About the first part, group of 8 teams, sounds interesting but the problem is that there is not much offer of managers as the demand.
Almost every group is searching for members, hard to find and many times they are using second accounts to complete a group of six.
The thing is that a manager has an option to search a group to join (from friend's list or same nation groups) but a group cannot find easily available managers to send a request.
Only from yellow pages - lol
About the second part of first idea, I believe there will be misunderstandings because of captain's decision and some members will leave.

The second idea is too complicate I believe.
The game engine is not so smart and we 'll have problems.
You see, even now the engine cannot make equal pairs. The draw of pairs is based at the current quality of every group team. Doesn't count the bench players.