He has two fire shrimp that would be gone day one. They are mostly not reef safe and nibble at fins of tank mates, etc. Cool fish, but I am puzzled at the suggestion for somebody who you are also suggesting easing into things.
Neat fish, but I would suggest captive bred for any large breed algae blenny, many wild specimens end up starving in captive reefs, especially newer setups.
Very docile fish and they love to sit high on rocks and observe.
I had a model citizen hawkfish (arc eye) for over a decade, but I think that is the rarity, not the norm. They are opportunistic and if hungry, well anything goes. They also grow rather quickly. Cool personalities though.
My easing into things suggestion was sage. But the OP has already gone down the rabbit hole.
As to why I suggested the Saddleback, I've observed its behavior to be similar to what the OP was seeking, and made a suggestion.