A 10g isn't big enough for 2 schools. Schooling fish like to have bigger groups, atleast 6. There isn't room for 12 fish in a 10g.
I'd either keep one school (preferably the rasboras) in the 10g by themselves and up the group to 8 or keep the betta and rasboras in the 10g and up the rasboras to 6.
Serpae tetras are really nippy, especially if they are in smaller groups so I would never keep them with a betta.
I would put the Serpaes in the 55g with other semi-aggressive fish or fish that don't have long fins.
I agree with Damon, big schools look awesome in larger tanks.
