The tank is looking nice. I always enjoy a tank at this phase. Every new coral and fish is something to look forward to! And the changes in the tank are so fast, it seems like you can actually watch the corals grow.
As always, a couple of things hit me when looking at the pictures. You've probably already thought of these things, but I'll throw them out there anyhow.
First, I'm not certain that adding another Coral Beauty Angel
to that tank is a good idea. I've never tried this personally, so I can't speak to it, but my gut tells me this could be an issue.
Then, assuming you do get away with 2 CB Angels in the same tank, I wonder how the aggression is going to play out when you add the Tang. I have always found that Zebrasoma Tangs and Centropyge Angelfish have a difficult time together, probably because they are competitors in nature for the same food source.
I also notice a lack of coraline algae growth, which is a bit unusual for a tank at this stage in its evolution. This is probably a direct result of the 8dkh alkalinity and 400ppm calcium readings. I would typically add a buffer and a calcium chloride supplement to my tank at this point. Generally, for best coraline growth, you would want to keep these reading on the higher end of the recommended range. Coraline growth is important because it inhibits the growth of cynobacteria and problem algaes, and provides the ideal conditions for corals to spread.