You can for sure mix dry=base rock with live rock! And it will seed itself on it own, and you can add it now! You should leave the shrimp in there for a couple of days, and test your levels dailyish. Just make sure you see the spike or can document that you didnt have one even with the shrimp in there. And the lighting is really going to depend on more than just the type. How many watts you have is important, along with type of watts. But i would just keep the lights you have with a FOWLER tank until you can buy nice lights that you wont need to upgrade. Look into the T5's.