You will still get a cycle. People who have an established tank and use all of their cured rocks in a new tank still usually get a small cycle. Take your time with livestock.. Always better to be patient
What do you plan on keeping in there? Every time I do an aquascape I drive myself crazy trying to make it a certain way and end up changing it a million times when if I just left it a couple days I would probably be fine with it. Recently I've been liking the more open scapes.
I bought a pistol goby pair and didn't see my shrimp for a couple months. I thought he was gone and forgot about him and then one day i saw a puff of sand and there he was.. So he could still be somewhere under your rock work or in the back..
Granular Ferric Oxide.. people run it in reactors so the top layer tumbles. It reduces phosphates in your system. You can look on Bulk Reef Supply or any other supply website they have info and videos