I don't think the timeline works quite right for it either, because the Hallowfall Arathi have been there with the crystal long enough for Faerin to grow up, and long enough that the "dark phase" is considered an unnatural development (it appears it started about the time Azeroth was stabbed at the end of Legion, which suggests they've been there for at least a few years prior to the Legion expansion if they saw "Beledar as light all day every day" as the norm).
AU Draenor seems to exist/have existed semi-parallel to our own timeline, both continue to move forward (albeit at different paces) and the event that would've made Yrel aware of the possibility of jumping timelines didn't happen until the Horde recruited the Mag'har while BfA was underway. If she followed, she'd most likely arrive sometime after that, if the Beledar is related to her, she would've had to arrive on Azeroth before the hijinks that spawned AU Draenor even happened.
This is all also assuming Yrel could figure out how to make the jump without the aid of the Bronze Dragonflight or any artifacts relating to them.