Think the severum would be a good match. As for the ebjd, I started with 2 as well and had the same issue. Came to the conclusion that one was male and the other female. Given more space (and hiding spots), they will hopefully get along.
As for Denison barbs, they are Asian river fish and do prefer a little colder water but I find that as long as you don't keep your tank "hot" they do fine.
As for Denison barbs, they are Asian river fish and do prefer a little colder water but I find that as long as you don't keep your tank "hot" they do fine.