Pre dragonflight lore was that dragons had lost their ability to reproduce, which seemingly was shaken loose, given ebonhorn wasn’t an aspect and was in hiding, I don’t think its all that out there to assume if there is an outlier (amongst the current aspects) it would be him or even kalec.
Now what we know about the black dragonflight (and the oathstone hatchings in dragonflight) is they need to be somewhere strongly in the presence of their associated flights magics in order to hatch. Historically we’ve seen black(and twilight) dragonflights having their clutch near heat/lava (obsidian sanctum, onyxia, sinestra). This would mean ebonhorn would have to choose a “den” in such a place, but given the history of the black dragonflight and their aversion to old god corruption beneath the earth, he would probably need some sort of reinforcement from a cosmic force that opposes the void/old gods, say the light? Or the emerald dream? Not that it would be laid in the dream, but maybe somewhere that holds a connection, so that the other flights can ensure that the future of the black dragonflight goes uncorrupted.