i think the abernants would be a family from out of town who were initially investing in the dam. aelwyn's learned to live with being kind of scorned wherever she goes and i think she'd be thrown into st lucia which she would thrive in and hate. i think she'd befriend shion.
secretly deeply invested in the occult, she'd conduct her own investigations into the nature of the curse and probably get disappeared midway through most fragments
if she reached lvl 5 hinamizawa syndrome, she'd probably become convinced that her parents doomed her to being the next victim of the curse and would kill them in a rage and then go on to try to blow up st lucia.
i think she'd rope shion into her spree and they'd probably spiral together until adaine came and confronted the two of them and then they'd probably turn on eachother. can see aelwyn using the underground sonozaki torture chambers and locked adaine up inside there for her own safety while taunting her about it