Phosphate is needed for a reef, Mg and Ca are only needed if you want hard corals. If you do get hard corals, you want an Alk test kit aswell
If you look at UR in the lighting section, you will quickly realise that the Acadia units have a nice high failure rate... They are bulky bits of kit also
Have a look at AquaOne units, loads of work's customers use and love them. D&D are worth a look also (many consider them the mother of all Halide makers in the UK)
The Clowns and Hawk fish are hardy and should be fine in a new tank. Gramma's are hard as nails also
I'd probibly do CUC after the spike and waterchange, followed by the Clowns the following week, then the gramma 2-4 weeks later and the hawk/goby a couple of months after the Gramma
All the best
Rabbut