Alright Ill bite on this one. I love planning out over-the-top setups for myself and customers its definitely one of the funnest parts of my job.

Tanks - Marineland no longer makes the DD tanks so I would go with either a DSA or Planet Aquariums 300g with PVC bottom. Pre drilled with corner or back overflows (your preference) and also pre drilled fro a closed loop on bottom with 1x 2" intake in the center back and then 4x 3/4" returns drilled on 2' from each end and 1' from the back and the front. And use a reeflo Dart/snapper hybrid pump to run the closed loop with an ocean motions 4 way.

Sump - Id go with a big sump as you will need to accommodate roughly 22.5 gallons of drain down for a tank with the 72*36 footprint. So I would go with a 48x24x16 sump refugium dimensions. That will give you about 35g of extra water holding capacity in the event of power failure. Also you have plenty of spare room to put the equipment. I would run 4x 7" filter socks, skimmer chamber, refugium chamber, to a section for the return pump intake. I would use a reeflo dart/snapper hybrid or possibly a hammerhead pump here as well so that it can feed your reactors, UV and the tank

skimmer - my preference being something along the lines of the reef octo diablo 300 or larger, or potentially the reef octopus POV series. I love the DC controllable pumps on these make feeding easy as well as using ozone easier.

Misc equipment -
UV go with uv sized for 400+ gallons, I like aqua ultraviolet for brands
Ozone - ozotech is a great company they make ozonators for more than just fish tanks and they are commercial build quality and have variable output which is nice when you need to crank it up cuz you over fed or are fighting a disease outbreak
GFO reactor
Carbon reactor
dosing pumps, I like the Bubble magus here cuz you get get 3 and then add up to 11 of them. I would start off running a bacteria source such as Microbacter7, reef biofuel, and a coral food mix
either a Calcium reactor or Kalkwasser reactor dependent on your coral goals, looks like mostly LPS so I would say save your money and go with a kalkwasser reactor
An Auto top off system either by and independent float switch or controller such as the neptune apex or the reef keeper elite.

Lighting, definitely would go with Radions either the Gen2 or Pros. Pros are nice as you will get more pop of color in the LPS from the near UV spectrum that is added as well as a more rounded color spectrum from the extra yellow. I have found that having all the LEDs in the same cluster with the same optics as opposed to multiple clusters has led to much better color blending and color rendition. I would say either 4 or 5 of these lights they cover roughly a 2x2 square. I have a customer with 3 on a 200g and it looks good. I would mount them 10-12" above the water and stager them with 3 in front and then 2 in the back.

And I would go with 4 mp40s for flow. less is better here (less output from 1 point source that is) you dont want to blast your corals with a jet of water you want a moving wall of water. multiples will serve you better.

This is how I plan on setting up my "realistic" dream tank lol