Hello again,
I am not sure what test kits you are using for testing NO3 and PO4, but make sure you're using something that is (agreed upon within this community) reliable, like Salifert or Hannah, etc. Seems like a lot of folks bash on ATI.
Just saying, I would focus on water quality and patience before rushing into more livestock... let the bacteria colonies grow a bit.. the tanks with DRY rock always take more time to stabilize than starting will LIVE rock.
Also, add more biodiversity, like copepods, phytoplankton, a variety of snails (some for sand bed, some for rockwork, glass etc.)
and "seeded" liverock, and coraline algae encrusted rubble/shells.
You are creating a bio diverse "reef," not just a FOWLR tank, right?!
Also, it is normal for any fish to be very "shy" and timid for the first couple days/weeks in a new environment.. they need to recover from stress of transportation and learn that they are safe in their new home. Don't worry if your Goby is hiding.. just make sure to sink a few pellets to the bottom for him to find, and verify he is eating some.
If any of your fish are being finicky feeders, buy frozen brine shrimp in a blister pack.
Shave/cut off a piece and thaw in a little cup of RODI water or tank water.. brine shrimp will make a good meal for any of em.
I also agree that you should have SOME PO4 and NO3 for any corals to thrive... otherwise they will slowly starve.
Practice good husbandry and patience, and keep learning and stability.
(Hope your wife loves your clowns! Happy they paired up for ya.)
-Drew