I used egg crate on the bottom of one of my tanks, its so the rock doesnt sit directly on the glass and risk breakage. i havent had any issues with that in the tanks that dont have egg crate so not sure how important it is. You want the rock in first anyways and the sand should go around it so it helps anchor the rocks.
I would go with two 1400 koralias at least, especially if you are wanting to go reef.
Look into reef octopus brand skimmers, they have a great reputation and afor the most part are affordable. I run an octopus, eshopps and remora on some of my tanks and really like them.
As far as stock, the only issue I would have would be with the blue tang. They really really need a longer tank, they are big swimmers not to mention they can get quite large. The angel may, or may not munch on your corals, its kinda hit or miss. And the cleaner wrasse, from what I have researched is quite difficult to keep, even the lfs
's will admit this and most of my stores dont even sell them for that reason. But you may have better luck than the average person.