I wonder...

Yes ghost shrimp seem to do well in brackish. My violet goby never ate the ghost shrimps in with him, but I wouldn't have considered it a serious loss if he had.

I assume they'd eat ghosties, but it's a matter of whether they:
1. See the shrimp (poor eyesight).
2. Can catch them.

I had put in ghosties for my F8 puffers, and they ignored them for at least 2 months (can't remember how long it ended up being). The shrimp seemed to do just fine and grazed on whatever algae was in the tank and any leftover puffer food. I'm sure they would have lived longer had the puffer not finally realized they were food, lol. Btw, I keep that tank between 1.005 and 1.008.