I think I'd play Time To Reflect over Fatal Push in dedicated zombies. Fatal Push doesn't seem nearly as good when you're not triggering revolt. And, in this deck, you'll almost always be triggering revolt in the situations you'd be using Time To Reflect. It might be better against Ramunap Red, but I'm not sure it's better outside of that. Time To Reflect is certainly better against Gearhulks. I don't know for sure if that's right though.

Lili feels too slow for the deck. Your creatures are small enough that the minus isn't that good. And slowly plusing her to get a zombie every turn doesn't seem like a great effect in what seems like an aggressive deck.

A replacement coming in Ixalan to consider is Vanquisher's Banner. Another buff for your team, plus a card draw every time you cast a creature. It adds up quickly. It's one I'm seriously considering for my tribal deck. The huge concern I have with it myself though is that it exists in a format with Abrade. Five mana to be killed by a two mana instant is rough. But, at the same time, it is kind of a must-answer card in a tribal deck.