You can cycle with any amount of live rock. The problem comes in if you want to add more live rock. If you add "uncured" rock after your cycle, you will start a new cycle.
So if you plan on adding more rock, I'd probably go ahead and do it now, and do your aquascaping at the same time.
Not sure about the hermit crabs.
28 Gallon Bowfront, 20 lbs live sand, 31 lbs of Fiji Live rock, 1 metallic green/maroon Brain Coral, Trachyphyllia , 1 5" rock with green Star Polyps...1 Bicolor Blenny, 1 Flame Angel, 3 Astrae snails, 2 Nassarius snails, 1 Bumblebee snail, 1 Electric Blue Hermit, 1 Emerald Crab, 1 Sand Sifting Star, 1 Cerith Snail