To answer your question though i would take Camms. He's been scoring decently and he'll also get you powerplay points. Avery isn't a very good pick up unless you're in need of penalty minutes. You can find better production on the offensive end elsewhere. Belanger's been one of the best Kings in real life but his fantasy value is pretty low. Better this year than previous years for sure though.
I find it pretty pointless to pick someone up just for penalty minutes. It's just one category. A scorer can light up a good number of categories with a good night which is obviously much more beneficial.
Fantasy aside, all three of them have played beyond expectations. Belanger has benefitted a lot with the rules. He's using his speed and has looked very good. Avery has actually been putting points up on the board and he's been a good physical presense for us as well. Camms, after a slow start, is scoring what seems like in bunches. He's running the point on the powerplay and has earned the confidense of the coaching staff. All three have been a big part of our early season success.