I can't really speak to the mechanics, but at least as a viewer it seems to me like it corresponds to what each of them saw. Azriel caught what might of been the tail end of some kind of ritual or ceremony, Gale's was focused at least in part with a magic elven d20, and Berg's was outright combat.
The thing that'll be interesting to see down the road if more elves start showing up is if this kind of permanent alteration magic is a straight-up thing for them. NPC/Monster blocks with rando extra abilities thrown in, or reskinning some of the more uniquely D&D creatures as part of their whole deal.
Depending on whether or not it's too iconic of a thing to replace, I could totally see the stats for mind flayers being repurposed as weird infiltrator elves with brain probes built into their armor.