Welcome to TFF.
Angelfish are not your best option here. Angelfish are a shoaling species, meaning they live in groups and should have this in the aquarium to be healthy. Five is minimum. However, at six inches body length with a vertical fin span of 8 inches, they are not small fish and need considerably more room. Some people will only have one angelfish, and while this "works," it is not normal for the fish and therefore something I do not recommend. I should also point out that if you did go for a larger tank, 4-feet length minimum, for a group of angelfish, you would at some point likely have another issue, pairing and spawning. If the tank was not very large, this would mean moving the spawning pair, or the other angelfish, either, to another tank, also large. It can get involved.
I don't know if your plan was to include the existing fish, the Tiger Barbs and Rainbow Shark, but this would not have worked; this species of barb is notorious for being fin nippers and such fish must never be combined with sedate fish or those with flowing fins.
While on the barbs, they need more in the group (I realize you are intending more), and it would be nice to give them the 30 gallon tank and increase the group to 9-12. This would be exactly what they require, though no other upper level fish. The Rainbow Shark could stay with them.
No mention has been made of water parameters for the source (tap) water, so I am assuming they are suited to the barbs.