White clouds are NOT suitable for a betta tank. The temperature requirements are too different and white clouds, being a SUB tropical species will not do as well as they should in the high temps bettas require. They are also active fish and require either the full 10 gals minimum, but preferably more space since they like to be in groups .
Cories also require more space than 5 gals, even pygmies. They are active little fish and again, love to be in groups of around 8 or more ( preferably more) 5 gals will not give enough space for such a group to rootle and forage about on the substrate.
Since each betta will have 5 gals of space each, it's really not suitable for sharing with other fish however small, just stick with shrimp or snails for tankmates.
If you were having just the one betta in the whole ten gals (which is a perfect setup in fact) then I would have suggested some small tankmates but since you're going for a divided tank with five gals each then single betta homes only with inverts for tankmates is best for them.
