need some help on my new 20G nano project

[aussiefishy]

here is what i am thinking. i want to transfer my corals from my 120 to a new 20 g, and here is some of the specs i can think of, please help me to finalize my plan.

currently i have these leftovers:

i have a 20 gallon sump, a aquamedic miniflotor skimmer, heater hagen 150W submersible, LR plenty and corals plenty.

i am thinking of using HQI pendants, can anyone give me any opinions on the heat issue and livestock suitability if i choose 1 20000k HQI as light? or any alternative? if HQI is ok, do i have to add antinics?

i will do the overflow plan, with a 500-700 GPH return pump... and no powerheads, but 1 internal filter, is it OK?

please help because i want to set this up right ASAP!! thank you very much!