I'll need to double-check the code for Dylan, but I would believe for a "Best Ending" that to be Dylan/Marie, and Ellie/Jules. Little Precious does seem to be tempering some of Ellie's more superficial tendencies so far. And if you make the "wrong" choices playing Dylan's POV in the Yoga event, Patricia steps in, calls him a moron, and makes it clear that he should pursue Marie.
Last I checked even Dylan didn't like Dylan/Emma, which can probably be dropped and no-one would notice. Starting to get the feeling that Emma was his intended LI, but as he became more popular, L&P changed his mind and decided to set him up with someone more classically attractive.