Child filing requirements

I'm way confused by this. My 18yr old student daughter had multiple income sources (2 W-2s and a 1099NEC (~$1500)), all of which amounted to about $6500, including $20 in interest income.

 

A. Was she required to file? She already did, because I thought she was, but now I'm second guessing it. She ended up owing >$200. I'm assuming if she didn't have to file, but did, there's no way to reverse that.

B. I'm now doing my taxes and it looks like if she didn't file, but was supposed to, I could have reported it on mine instead? Is that right?