Boraras are alright. I had them with cherries, but I cannot vouch for the fact that they never touched the shrimp. Only because i didn't observe it, doesn't mean they didn't do it. Don't put CPDs, guppies (endlers included), scarlet badies, or really any fish. I'd put otos and maybe dwarf cories if you really really want fish. A good rule of thumb is that if the smallest shrimp size could potentially fit into the fish's mouth, be sure they'll try.
Especially with high grade shrimp like BKKs why risk it? And most shrimp are colored as wee little guys already, like the Fire reds are red, even the juvies!! You can be sure a fish that can see them will chase them as these colors stand out (maybe not directly BKK, but again, why risk it?)