Just came up with a new idea for communicating with team members.
A flag/beacon system.
Touch anywhere on the map( as long as it is not your team member) and a colored beacon will appear for all to see.
The colors would be Red, White, and Black.
Red means there is an area that needs ink.
White: means that the area is secure
Black: engaged in fire need backup
I think this would be a perfect way to implement team communication(If Nintendo is hell-bent on No voice chat) and it would be balanced too. For example, a team member may set a red beacon indicating to both friend and enemy that an area needs to be inked. In doing so everyone may arrive in the area or, another team member could stay back and ambush incoming opponents. There would also be the question of which team sent out the beacon for mind games of course.