Me, Myself & Irene meets Death Defying Acts – "When two young illusionists with multiple personality disorder start dating, they must figure out ?who? will date ?whom’; so their love lives will not self-destruct."

Yes, if that's the case, it will at least be a tumultuous love life! I think my loglines always get created out of some kind of 'contradiction' popping up in my mind. For me personally some kind of contradiction should ALWAYS be in a story. If this is the right one for this logline remains to be seen. Now I'm drinking no coffee anymore and don't work late at night, I hope (in the near future) my loglines will get - let?s say - clearer.... and my mind also-

Thanks for clearing things up Joel, maybe it is to much. Have to think about that. And thanks for the rewrite of the logline. It's food for my brain...

Can two people with split personalities find lasting love when one pair of their multiple personalities are in love while the other pair hate each other?

and also... if the second character is a con-artist (as the twist), then they are not primary protagonist, and you should consider re-working your Logline to focus around the single primary protagonist. Just spitballing here but:
"When a young illusionist, struggling with multiple-personality disorder, finds a romantic relationship with someone who seems to truly accept and understand him, he must convince his band of 'internal passengers' to play-ball, or risk ruining his one great chance at happiness"

perhaps not perfect, but it focuses the logline around the primary protagonist, raises the stakes, and leaves the mystery open for the 'great reveal' later in the script.

... just another 2c!

Not necessarily two themes, but two devices. Two things, each of which require us to suspend our disbelief and just 'accept'. So one of them has a strange multiple-personality-disorder which they have the ability to consciously control. (Ok, I can accept that).... and he meets someone else who happens to have the same strange condition... (mmmm a bit weird and 'strangely convenient')... and that person has exactly the same obscure profession Illusionist.... (now I'm feeling quite stretched for credulity)... Thats what I meant by 'double mumbo-jumbo' in this case.

look, perhaps you can make it work, but personally, I found "Me, myself and Irene" to be a bit annoying and difficult to 'suspend my disbelief'... now you're suggesting a plot which "doubles-down" on that film's worst characteristic (I.M.O), the exaggerated multiple personality disorder, , and expands on it further by making it controllable. Just my 2c.

Good luck with it all anyway!

That it's unrealistic yes. But a lot of comedies are! Double Mumbo-jumbo? pitfall ? I know the Double Mumbo-jumbo? pitfall. But that's about two themes in the same movie; for instance religion AND aliens.

And they are illusionists. One of them could be a con artist {twist} pretending to have multiple personality disorder (If that's not Double Mumbo-jumbo?!) We don't know, that's the suspense.

Why pretend? Let that be part of the story.

In this comedy they can!

I agree with Richiev. It sounds like it may be quite 'convoluted', that two Illusionists, both with the same unusually (unrealistic) mental condition, which they can consciously control, happen to be working together and attracted to each other in this way. It's straying towards Blake Snyder's - "Double Mumbo-jumbo" pitfall, and the audience may find it hard to connect with the concept and suspend their disbelief.

I would drop the movie reference at the start. Your idea is strong enough and I disliked me, myself and Irene. Let the reader form their own opinion.

Do multiple personalities really work like that, they can pick and choose which personality from one will date the the chosen personality of the other?