I had a slight look around the forum and I haven't found what are the exact rules concerning the 3vs3 teams when it comes to playing with different partners during a single season.
I have a few friends of mine on Icecrown who pushed in the gladiator range and confirmed me, supposedly from the answers they got from different GMs that inviting and playing with different partners in a 3vs3 team during a season is subject to a team disband.
(Potentially no more than a single player swap might be allowed)

I've been playing for years on AT/Blackrock and with the way the mmr works there we are pretty much able to play with anyone in a same team, rewards then are given if certain players meet the requirements.
On Icecrown with the blizzlike mmr system I am wondering what exact rules are set if there are any about the ability to play with different players/friends in a single 3vs3 team.

- Am I able to invite any amount of players in my 3vs3 team during the season, playing with them, and still obtain the rewards if I am the only one that meets the requirements?
If I am unable to, what are the exact limits set if I do not wish to have my team disbanded at the end of the season?

- If there are such rules in place, are they the same for the 2vs2 bracket?