I've seen those African shrimp's at That Fish Place before. They are really neat! They stood on top of one another in a triangle formation catching their food!
I've only seen them that once though.
Keep in mind some betta's will attack anything in their tank and might get stressed out over the presence of something else in there. I have one that will attack anything that moves, and then I have some that are very passive and coexist with other creatures no problem. :)
Make sure you research them fully and know that you have the right tank setup.
10 Gallon Divided Betta Tank
Shaman the Halfmoon
Durban the Crowntail
20 Long Community Tank
9 Glowlight Tetra
6 3-Lined Cory's
A mob of Ghost Shrimp