if you leave it in with or with out the "air shafts" youll get a build-up of bacteria, ammonia, nitrites, nitrates, and thats all of the stuff that your LS eats and thrives on.
If your tank has been set up for only a week it hasnt cycled yet. every tank when set up will cycle. a cycle in lamans terms is when the tanks ammonia and nitrites and nitrates will spike (killing about all your your livestock). damsels can live through it and your LFS will reccomend them to start your cycle but use a dead shrimp or something. much more humaine.
yeah you could definatley do live rock it will actually filter moer than hanging one. and a few pieces of sand will filter more than the UGF. after i removed my UGF my water levels were better, my water was cleaner, and the world was just a better place
but seriously it is a good idea to just take it out. and tank being so new wont hurt anything. do you have an extra tank...a QT? id put the fish in it until the tank cycles or they will all die..
i learned the hard way.
but getting LR will be the best way to go for further filtration.
sorryso long