What all is in your sump currently? Most people run a bed of sand, some rock rubble, and usually some macroalgae (like Cheatomorpha) to trap nitrates. Any algae will need a light, but a cheap twist bulb in the 6500k range will suffice just fine.
Ride out the cycle, once everything get's to zero, you should be golden. Be ready for a diatom bloom once you get your lights on.
For the silencer, you can take a film can, and then either punch two holes in the lid, run your intake hose into one and then fill it with some cotton batting, or you can punch a hole in the bottom and one in the top, run your intake into one side, and then a short length of tubing into the other side. Make sure the 2 sides are past each other so that the air has to go into the first tube, and then go backwards to get into the other tube (does that make sense?). Just make sure it's above your skimmer and it shouldn't flood.