I prefer not to keep rocks in the sump. I used to and they were collecting detritus and becoming more of a problem than a help. If you're going to turn part of the sump into a refugium, then live rock rubble is acceptable.
I love the EcoTech Vortech powerheads. I run two in my 155, I was actually going to suggest that you might want to look into the MP40's for this style tank. I think you'll be able to get better flow than you will with a conventional power head. As for it's placement, probably better if it's on the side of the tank. This will cross with the return pump and should create good flow, but a lot will depend on how your rock work is set up as every tank is different.
We've been researching LED's pretty hard lately. I'd like to cut down on the electric cost, especially since we're about to move. It seems that if you do all your research, DIY set ups seem to work best. If you're not a DIY person, Acan Lighting makes fabulous LED fixtures. I've seen them on numerous tanks growing everything from soft corals to SPS.
Live rock does not need lighting, but in order to get that purple algae (coralline) to grow, it needs lighting.