Eastern Suburbs play Waitakere & Southern at home and Tasman away.
Canterbury play Tasman and Waitakere both away.
Team Wellington play Auckland at home and Hamilton away.
Considering the above fixtures - Eastern Suburbs currently are equal on points with Team Wellington and 1 point ahead of Canterbury, have a game in hand on the other two and a vastly better goal difference - I would say that Eastern Suburbs are in the best position to join Auckland with a home semifinal. At least it is in their own hands while it is not for Canterbury and Team Wellington.
As an aside would Auckland through using "squad rotation" consider giving 3 points to Team Wellington with the aim of avoiding playing Wellington again in the semifinal?