You can have live rock in DT or the sump. Some people use less rocks in DT (for negative and open spaces) and put the rest in the sump; no difference
And you can break them into smaller chucks for greater surface area. You can place the live rock in any tub with saltwater, shouldn't be any problem. Bacteria are not as finicky as fishes/corals; they are bacterias after all :P Just make sure the salinity is above 1.018.
Just a word of caution (which you might already know), those LR are phosphate factories
