Yeah, the angel and acaras would likely eat most 2" and under torpedo shaped tetras/fish.
You could go for the coin/disc shaped tetras though (taller bodied to not fit in mouthes like, candy cane tetras, black phantoms, etc).
My personal opinion, I stocked my 5 foot 100 gallon with schools of little fish (30 cardinals, 20 rummys, 20 espei rasbora, etc), while they are nice little fish, from afar, they don't really stand out like med-large size fish such as your congos and rainbows. They are better for making the tank look bigger (size ratio). I personally think I should have gone with med-large fish. Maybe larger schools of little fish would look better, I am not sure. However in my experience, the more heavily planted the tank, the less active the fish became, which pretty much negated the schooling behavior that was a attraction. Before the tank became really planted, the little fish were very active and was a sight to watch, even from afar, but with more plants reducing activity and the plants rather hiding the fish, it just became a nice plant tank, but not so enjoyable as far as actually seeing the fish and them being active. I am planning on selling all my little fish and changing the stocking to med-large fish or just Pinoy Angelfish with a few other additions to fill the tank in. I would have gone back to non/sparsely planted tank again with active fish which I did enjoy, but since I spent a bunch on plants and equipment, I will go for the change of scenery for now and just do plants with larger fish.
Hey, even if you decided against small fish, but still wanted to change things up, I guess oddballs are another consideration. Still do your research on their sizes, temperament and whether they are plant friendly or not. That is another stocking plan I was considering over the angels. Haven't quite made up my mind, I just like the colors of the Philippine blue angels. But odd balls are the fish that drew me to this hobby, just the ones I really want get a bit too large for the tanks I have to keep them their entire lifespan.