I haven't reach 600 yet. But for the last two question, Xueyan's parents were the previous dynasty's royal family. They were attacked by traitors in their dynasty.
Chenyi's father killed the traitor before they could ascend the throne. Since then, the Ao family took over. When Chenyi's father died, his brother became the current emperor. They shouldn't be related by blood. Not sure of the age tho. I'm still at 500.
