Calamities explained

[Naria]

Emet-Selch does state that you don't have to be a shard of one of the original Ascians to be "raised up", just that the process is just easier if you are.

I agree with you and Snow, Elidibus is desperate. It doesn't take a WoL to kill an Ascian, Galuf and Gaius both have shown that. Ardbert and co killed Loghrif and Mitron on the First as well. Emet-Selch's dialogue implied the ascended Ascians were considered somewhat expendable and that it wasn't rare for them to die. If after Lahabrea's death, however, every Ascian that is killed can on longer be replaced it does explain his desperation to kill the WoL and reset the clock as it were. With the WoL's death (and that the Scions) the knowledge that the Scions have gathered on the Asicans would no longer be actionable and would hopefully be lost.

Eli goes from, "hey isn't the WoL interesting with how gifted they are with the Echo" and "we should be on the same side" in the ARR patch story to personally trying kill them in the Stormblood patch story. So whatever changed his attitude had to happen between those two points. From what we know, Lahabrea's death does seem like a good candidate, but since the WoL wasn't the direct culprit it makes me wonder if there is more significance to it beyond simply the death of one of the unsunderd Ascians.

I could be overthinking it though.