Frozn play extremely well with anyone that provides an advantage in losing. That's not to say you should lose with those characters, but they help keep your opponent guessing. Ahkab, Bonnie Ld, Hawkins, and Kristin will leave you both 3 star spots open for your favorite Frozn.
You can also make your opponent "pick their poison". Freaks Frozn makes your opponent choose between eating poison dmg or taking a huge slap in the face the following round. With options of Grudj, Varoslav, Baldovino, and Sah Brinak you can potentially leverage pillz advantage in the mix as well.
Something else that I am personally experimenting with is Timber! It's not ready for prime time yet, but he is a huge help when you don't have the bonus, and gravy when you do. Good luck!
Vortex probably has the best synergy With frozen at the moment.
Something like this http://www.urban-rivals.com/presets/?id_preset=2280039&list with a few tweaks depending on the weeks meta usually does well.
Yeah, the big thing is that, if you want to use Frozn's bonuses, you have to make your foe KO the non-Frozn people and survive it. Pcats are one way, but also telegraph your intentions. Vortex work, but are a tad predictable. Oddly, I think some of the big clobberin' people are in order, like FPC or Junta ... if they take it on the chin to keep your Frozn under control, they take BIG hits. In contrast, kill the weaker side, Frozn get their hits in afterwards.
Mix n match offense, instead of the "HERE IS MY STRATEGY" style of a Pcats bluff.