The newer ASM cone style skimmers are ok, but I think the old ones are not worth the money. NYOS, Reef Octopus, SWC, even Bubble Magus makes some decent skimmers. Skimmers are all about the pumps- how much air they pull V.S. how much electric they use. The sedra pumps ASM uses are good pumps, but use a lot more juice than some of the newer pumps. I would suggest a skimmer rated for 1.5 to 2 times your total system volume, as manufacturers loosely rate them.
I'm not familiar with any of those companies you mentioned except DSA, but I will say that it's best to have a shallow tank with a large footprint for a reef. You are going to want to be able to easily reach the sand bed and have plenty of real estate for corals.
I recently had a DSA 105 rimless, and I was disappointed with the glass thickness they used. My tank bowed considerably when filled. I kept it for a year, and nothing broke or leaked, but still....hard to sleep at night knowing this.
I don't use any reactors, but if you like them, many companies offer them. Bulk Reef Supply makes the reactors built out of the canisters used on their water purification units. These are pretty tough.
I don't think you need a closed loop. A few Vortech Quiet Drives and you will have all the flow you need.
I don't use UV
sterilizers, as they kill whatever goes through them, good or bad.
Lighting is personal preference, but the right LEDs need no supplementation, so if the efficiency of LED
is what you want, skip the unnecessary pc
or t5 supplement. If this is a reef, I would get the light you plan to go with immediately. Corals don't do well with lighting changes. Better off starting them under the light you plan on using.
I can't make any sense out of the Custom Aquariums sump page. I would just make it myself from a standard glass tank. It will end up being a quarter of the price.