Aether sensing: Sure! Izunia probably pings really strangely - there's not really anything in XIV that uses light as a direct element except for like, Hydaelyn herself, and that's his primary alignment. He's also packing a lot of aether, of the "penultimate/final boss" tier, though if Ruto is paying attention there's a couple of slight drains on it (primarily to Astolfo). If he's in his armor form, well... Sorry about the Thordan flashbacks.

As for Echo, GO FOR IT just ping me if you wanna set it off, Izunia's got. uh. he's got a History.