Welcome to the forum and the hobby. A 55 gal tank is a great starter community. However, there are some problems with your stocking plan. I'll go over them.
6 Celestial Pearl Danios
- these are a very small shoaling fish and would likely be eaten by the angelfish and rainbowfish. I think you should replace these with a different shoaling species that won't be seen as food by larger fish. 1 Dwarf Gourami
- These are not recommended with angels as both are territorial. They also commonly carry disease due to a lot of commercial-scale inbreeding. I think another gourami like the thick-lip or honey would be a better choice if you want a gourami. 1 Marble Veil Angelfish
- Angelfish are shoaling and need at least 5 in a group. They can be aggressive with other fish if there are not enough angelfish around. And again, they don't work well with gourami. 5 Golden Barbs
- Beautiful, but they like cooler water than most other tropical fishes. Unless the tank will stay below 75F, then these might need to be replaced with another fish. 3 Eastern Rainbowfish
- These guys are pretty large and active and would bother both the angelfish and gourami. They also need shoals of 6 or more to feel comfortable. 4 Nanus Cory Cats
- This could work, but when keeping cories it's always best to have more than 5 of them; they are more active and bold in larger numbers. In your tank you could easily do 10 of them. 1 Clown Loach
- Clown loaches get too large for a 55 gallon and are a shoaling fish. They can become very nippy when kept alone. Best just to leave this guy out.
The largest problem I see are the angelfish, gourami, and rainbowfish. They all conflict with each other, and having that many larger fish in the tank will make it a little overcrowded. I think you'll need to chose which one you like best.
As to your feeding question, it's fine if fish don't get fed every day. Their metabolisms don't work exactly like ours, so they don't need to spend as much energy on heating their bodies. Plus, fish are pretty good at finding food when they really want it.