my tank is doing ok. i have been battling hair algae recently...glad to know the corals are still doing well!
my previous frag tank was entirely separate from my display. it required additional equipment (i.e. auto-top off, return pump, heaters, etc) and additional time for water changes. after some time, i got tired of maintaining both tanks and as you know decided to shut down the frag tank.
i do not like seeing frag plugs in my display, so i manufactured a small frag tank and incorporated it in my sump area of my current display. it is gravity fed from my display and then gravity fed in to my sump. it has one small powerhead for circulation.
will your frag tank act as a quarantine tank too? my advice is to keep it simple whichever route you decide to take.