Trying to throw logic in here is a bit iffy. You could logic your way to a Cece ending (intense emotional bond created by the event), a Linda ending (realize you always loved your best friend), a Steph ending (realized none of the lies mattered, you never stopped loving her), etc. Saying Lexi is "logically" the canon ending kinda ignores the rest of the story being developed. It's not a bad choice, and it may be Drifty's cannon ending, but if you've finished the game, it's not the only possibility (and wouldn't be my guess, either).