Only daenarys has a reason to still fight
First some facts: Cersei Lannister is not as evil as Joffrey. Stannis is dead. So is his brother. Jon snow does not want to be king of westeros. Neither does Sansa. The martels, or the tyrells don't want to rule westeros.
Only dany has a real reason to fight a war for the throne. Everyone else is just upset over revenge for things their families did. Cersei wanted Joffrey to have mercy on Ned.
To this end, I don't believe Jon snow will be eager to help dany fight the lannisters. But I don't think he will help the lannisters fight dany either.
And if everyone could come to their senses, this is really between two power hungry females. Dany and cersei. How many will die for those two biatches? Jon snow and Jaimie Lannister I can see being the ultimate heros of this story