The chief's daughter burn was caused by outsiders, in their Village, burns are not that weird, most of the time it's something to be proud of! Because it's part of training for different roles, dances, traditions and Jobs.
2 Acolytes in training are chosen every 10 years, since the last EM of fire was seen. Isaiah and Lyre were lucky to be chosen not long after Ochre woke up.
Sun acolytes are the main helpers of the leader of the village, they take the more important roles like that of teachers, caretakers or guardians. They are the ones to report anything they deem important enough that the chief has to step in for.
You can see who is still in training by the type of shoes they are wearing, children usually have closed shoes, teens and young adults use open ones while most adults are barefoot to show off the proof of their coming of age.
Acolytes have a higher tolerance to fire and tend to use it for A LOT of things, Ochre's fire being naturally blue leaves them excited for the future.