My only thought is, in a 110 you wouldn't see your mandarin very often. I lose mine in my 55 all the time.
and mini bristles don't really interact from what I've seen. One filter feeds and the other consumes algae. That makes destroying the bristle population with a harlequin not worth it, that and keeping that shrimp alive would be costly.
I keep my mandarin alive with ordering pods
from reefs2go.com every other month to keep my population high. I haven't been able to get a nice reproducing population in my tank's refugium, hence continuing to restock. The nice thing about reefs2go is that they offer BOGO deals and I end up getting ~2k pods
in one go to release into my system. They are pretty nice looking pods