Late to the party for this question, but there is one more aspect of team chess that is very important that may, or may not, be considered etiquette; but it is definitely a firm guideline for team chess.
Don't lose. A draw is always fine, but try not to lose ever. Of course, this is not always possible, but playing on a team has a lot more responsibility than just playing for yourself.
I know that sounds funny since your opponent is trying to beat you, but you have to try to play positions that do not give you a high chance of losing, which puts your team behind the eight-ball. If you are a wild, out-of-control attacker, I probably do not want you on my team.
I have played a lot of team chess over the years, including being a multiple winner of the Northeast Chess League (it was a thing in NH and Massachusetts a long time ago), and finishing second in the open section of the U.S. Amateur Team East tournament in 1993.
In both of these events, you have only four boards, so losing forces your teammates to go 2.5/3 in the remaining games if they want to win the match. This is, obviously, a tall order.
So keep that in mind when picking teammates, and when you play in team tournaments.