What are your interpretations for engaging an ally concerning its maneuver costs? I've always assumed that you just spend a maneuver and take that action. But I don't even see that maneuver anywhere.
Right now, the best I can see is that it would cost you a maneuver to move to a new location within Close range (assuming your ally is in close range). But after that your considered Engaged with them.
I'm also assuming that if the encounter begins and the party is grouped together then they're already considered an engagement, so no maneuver is needed to engage your ally then.