I posted a thread about my take on Mei Feng a couple weeks ago, so I'll just reiterate what I said there.
1. Mei is purely combative, so having the support crew to help with objective running while she fights is key. I like "Seismic Claws" with her a lot, and others have mentioned "Misdirection" and "Wings of Wind" too. Be sure to keep a decent cache though, in case you need to burn a stone for the Mask trigger.
2. I like Metal Gamin a lot. If you're going up against a list with Constructs, all the better. They're resilient, cheap, and provide a decent means for her to Rail Walk.
3. TT Archers would be magnificent. If you can find a carrier for "Blot the Sky", and keep them in range of the carrier, all the better.
4. Kang is an all around great Henchman. As a secondary combatant, he pulls his weight and then some. If you're going up against Ressers or Arcanists, taking him with the "Hard Worker" upgrade are pretty much auto-include.
5. Emberling is the best totem she can have alongside her. What I like most about it is that it's not Insignificant. If you need a model to drop Scheme Markers, he can easily do that for you.
Good luck!