Wes,
I'll be building a similar sump, if I can ever find a 55
You're plan should be fine, I would maybe switch the skimmer and fuge sections to allow skimmer bubbles a little more time to break. Make your inlet/skimmer sections big enough any filtersocks, reactors and your skimmer (with some room to upgrade).
If you're going to have an ATO, a small(less than 6 inches) return section will suffice. As far a bubble traps, on my current sump I used a 2 baffle bubble trap. It looks just like the regular 3 baffle. one but without the last baffle. You end up with and over then under water flow pattern. Space the baffles around 1-1/2" apart, 2" is even better. This slows down the velocity of the water so bubbles don't get thru as easy. That cover everything?