Wow, a lot has happened! I love the pics since my last visit. I don't like how they display in the new forum software, but, we'll have to live with it, I guess. I was thinking that if the macros, specifically Caulerpa, are a good and nutritious food for your tangs, and if they eventually wipe it out, then maybe you could grow some in a bucket with an airstone, and a grow light, then add to the tank when you feed your fish.
Also, you need a blenny of some sort, one tough enough to hold up against the damsels, but one that won't bother anyone else. You have plenty of herbivores, so I'm thinking about one that is an omnivore or carnivore. I think that a molly miller would be a nice addition. But, I'm extremely biased toward blennies, LOL, as you know. There are some less aggressive than the molly miller, but may not last with those damsels. However, you are the one that will be watching, observing, learning, and loving your tank, and are at the helm of it's future. And, of course, we are along for the ride enjoying it all, regardless of the decisions or preferences that you have.
I thought that I'd end with how fantastic the tank looks, and the fish bring a menagerie of color to the tank. I imagine watching them in action and can see hours of entertainment. And, talk of adding sponge and an angel is quite exciting. Other than blennies, of the SW fish, I'd say that angels are my next favorites. They have so much personality and most species are stunningly beautiful. BTW, there are some nice medium sized angels that would do well in your tank, but, they're quite pricey compared to the dwarf angels. I'm so glad that I'm finally able to log in to this site again. I felt lost when I tried to come back a few weeks ago.