A stock list is a good place to start but the tank parameters will tell you when the fish limit has been reached... as long as you add them slowly.
Also, the 1 lb per gallon of rock is and old paradigm. If you are going to use a RDSB and a lighted fuge, you could get away with very little rock. This is the way it seems that most are going. This allows you to have a very open aquascape so detritus is less like to build up and cause problems. It also leaves more room for corals and fits into your less is more plan. Securing the rocks together and not stacking them against any of the glass seems to be a common practice now. I'd use dry rock from BRS. Yep, you'll find most here really like BRS. I think I've sent some of their kids through college!
In a 75, a closed loop may be over-kill. +1 on at least one MP40. It is a lot of money, but you won't regret the purchase. Maybe the $ saved on rock could go toward it. Save your pennies. You don't have to buy it right away, but don't waste cash on lesser products.
Look at the DIY forum before you build your LED fixture. 60 3W Cree's sounds about right for a kick-a$$ 75 SPS tank, but there are some other issues like dimming and programming to consider, particularly if you are going to use a controller. If I knew how to post a link I would. Maybe someone else will help us out with that.