I doubt it matters (at least I hope so). Making the ending dependent on a task you couldn't predict the outcome of is not a good project. Besides, from what I tested, Omeluum's "help" does not start a dream sequence. Most likely, the main consequence of the quest is a ring that should protect you from mind control if you've used tadpole too often.
I actually did test spamming that repulsor ability over and over in a secluded zone and kept on going to rest over and over to reuse it, and mind you, all my saved characters up to this point have not used tadpole powers a single time thus they had not triggered a single dream, so my finding was - spamming repulsor does trigger the first dream (you gotta rest a lot and spam that ability like a madman), the one where the voice says 'where are you?', but further spamming didn't trigger the other dreams, what I found to be quite odd.
Which is why I was wondering if that tadpole 'getting stronger' will have any consequences. Sure, you had no way of knowing, but you could always reload. Not to mention - hag's offer is similar, takes your eye away, tells you the tadpole is steeped in netherese magic and trusting Volo is just dumb. Still, each of these tadpole removal options has dire consequences. Also, I don't trust Omeluum, he might sound quite benevolent, but in the absolute best case scenario, he's a neutral party, he didn't mind working with a damn lich for crying out loud, then he changed his mind about his lich friend... also, Society of Brilliance is a neutral organization, in comparison Harpers are generally considered good and Zentharim are evil.
