An immediately buildable police unit makes sense, although I don't know if graphics are available. Perhaps SWAT could be somewhat strengthened, but not too much - Authorities are already clearly stronger than the Company (well, they should be!).
For Wonders - how about, at the Fast Food Joint, The Grill? (Do they all have to be eponymous?) It could cause pollution, but also happiness and perhaps count as a granary.
It's too bad the Military Base can't allow you to build elite units.
I'm playing a new game as the Survivors. I thought it was going to be easy this time. I torched the Graveyard, retook the School, captured the Hospital and the Factory... that's when the Zombies started really hitting the other factions, and took the Factory away from me! Hannibal Smith only barely escaped by jumping into my first Mean Machine and escaping with a couple HPs left, after everyone else was killed.
I was able to get a round of Mean Machines built, though, which has allowed me to preserve the rest of my buildings. As soon as I can get half a dozen defensive units together, I'm heading back to the Factory.