I'd groan very loudly if our missing Ascians got dealt with off-screen
Emet also told us the duties of Altima, Halmarut, and Pashtarot; meaning Deudalaphon is the only Sir-Not-Appearing-In-This-Game of our missing 4 (and Schordinger's Emmerololth... and the 2 extra Ascians in 2.3). I'm hoping that if they got offed at some point we at least get an Echo vision of it, or they're involved in Pandaemonium SOMEHOW.
Of note about Lahabrea/Pandaemonium
Emet also mentioned of Lahabrea that he'd "brought forth phantom beings of the highest complexity". I'm... thinking this was foreshadowing about Pandaemonium... but not sure if it's the resting place of said creatures... or the name of the most powerful of them considering the stinger...