Well from my thoughts on the tank and your bio load, you are going to need at least 1/3 the water volume that is on top. So figure your tank is ~700g, you will need at least 200g underneath.
Your skimmer will need to be HUGE as it will need to skim at least double your water volume because of your stock. You will need to have a lot of room due to the fact that your water flow from the drains will be quite turbulant. There will be a ton of bubbles in the sump and you will need a couple of gates in the sump to get rid of the microbubbles. Also, with a skimmer that skims 1500g, you are looking at a footprint of at least 18"x18".
You will need this much for water quality. Without this, you will be doing massive water changes every week.
With a 700g tank, you will be looking at around 100g weekly changes.
I would say here is what you will need:
200g Sump/Refugium
Skimmer rated for at least 1500g
2 return pumps (Reflo Hammerheads) due to the depth of the tank