You need:
1) some water circulation equipment (powerheads, AC filters)
2) a way to meaure specific gravity (hydrometer, refractometer)
3) some test kits (NH3, NO2, NO3, pH)
That is a
very basic equipment list. There are other things, such as a skimmer, that aren't "needed", but are very beneficial.
I would go with 20-40 lbs of LR, depending on what you want the tank to look like.
I don't know what kind of substrate you want to use (LS or dead sand), but I can't recommend an amount in lb. What I
can say is that you'll probably want to go with 2" or less of whatever you use, unless you try for a limited deep sand bed (DSB).
Thinking of plumbing in a sump or refugium is a great idea too, but I don't know how involved you want to get.
A great place to discuss a tank of this size is
nano-reef.com. I am a member there and it is a great community of people dedicated to reef (and FOWLR) tanks 30g and less.