One thing about White Clouds, though, is that they are coolwater fish, and shouldn't be kept above 75 degrees (that's the high range for their safe zone). So, if a person wanted to keep them with Bettas, the compromise would have to be 75 degrees, which isn't bad for the Betta, and isn't bad for the Clouds.
Balas are much too large, and much too aggressive, to be kept with Bettas.
Barbs and Tetras are BIG no-nos (too nippy).
Guppies, Mollies, Swordtails, and Platies simply DO NOT work in the long run. They either nip, or get nipped on.
Ghost Shrimp get eaten joyfully.
Snails sometimes get eaten, depending on type.