I had a betta for a while and added some white clouds with no problems in my 29 gal. The white clouds and zebras liked to 'school' together and the betta didn't seem to care about any of them. Of course, it may have been too busy hanging out with the blue gourami to care. For some reason everywhere one went, the other was close by, and they even shared a small cave together at times.
Anyway, back to topic at hand, from my experience, betta and white clouds should get along, but that was just me.