A tang is not likely to go well. The smallest species of tang is the tomini, which reaches 5-6 inches. While a baby could theoretically live in there for a few months, it would outgrow the tank and start having problems rapidly. As far as an angel goes, you are also low on options. However, a cherub or flameback angel might be able to live in there. I wouldn't suggest it, though. It would likely become very aggressive, and rule the tank with an iron fist. If you were okay with it being the only fish, it could be a suitable option. Instead, I recommend a royal gramma, meicanthus blenny, or springer's damselfish. I hope that this helps!