Thanks for the advice so far, I am having to re-type this due to got timed out for being busy working haha.
Tank A = old tank, Tank B = new tank:
So, plan is to bring in trash cans, what I did when I moved it the last time. Drain water from A into cans, remove live rock and corals, capture livestock and put them in the the cans with water circulating. Drain A completely into cans. Move out of the way, bring in Tank B. Add new sand to B (sand in A is really old and 2-3" deep and I had a red-tide event from a pistol shrimp a few years back so I don't even want to touch that sand. It is also from all my fish tanks going back probably 30 years). Start filling B from cans. Let sand settle, add live base rock, again let sand settle. Add rock with corals and then corals, and then fish (only 3) and other cleaner crew. I will have water ready to add if needed. Then pray.
Plausible?