looking good. I am in just about the same stages you are in with my 6x2x2 true 180g display. Like you were with you 80/20, I am at a roadblock waiting for my contractor to brace and support my flooring before I can move forward. Everything else is ready to go. 20 frags in a frag tank and 6 fish spread between 3 QT tanks. Hopefully it gets wet after Christmas to start the cycle.
It will be nice to follow my progress along with yours as they will be just about the same age. Keep up the good work.
IMO I would have waiting on the Kole Tang (My fav tang). Being the first fish he will claim the entire tank as his and will battle any new additions. I am starting with a peaceful bunch of fish followed by a pair of clowns and a lawnmower blenny to control the ugly stages. THEN I will add 2 tangs at a time for a total of 4 tangs. I am sure you will be ok but tangs in the early stages can lead to aggression.