I think Man Man will stay alive until the villains find out about the twins. First, in the opening clip, the forehead kiss linked to the scene in the ending clip where everyone goes outside of the wood manor. Including Chao Feng, Qingkui, and the real Husui. At this scene, Man Man is still alive.
There is a scene in the trailer, Man Man is lying on the ground, the twins stand a bit far, a void man (perhaps the twin brother of Dingyun's subordinate or Chao Feng) near Man Man, and Youqin. Perhaps this is where Man Man dies.
It's good if Man Man can be reborn since she's a bird, but surely she won't revive even until the end. It's Husui and Jia Luoluo who accompany Yetan in the void.
I want to believe the fireworks scene (and the hug) is either the ending or the last moment before their final fight.
In the novel, Youqin sacrifices himself to resurrect Qingkui. If they go on this route, hopefully his soul can be collected again or at worst they have to wait for years until he finally return (just like Love and Destiny, ML finally returns after 300 years).