I doubt either of them will successfully transition, but if one of them were to defy the will of God by breaking our expectations and actually go through with it successfully, I'd put my money on Chris being the one that actually gets it done.
As lazy as Chris is, he's nowhere near as bad as Phil, at least in terms of putting in effort (which is saying something considering how little effort Chris puts into anything).
Chris may suck at passing, but at least he can pass for a middle-aged homeless bag lady (at least from a distance, anyway), that's a hell of a lot more feminine than Phil can ever manage.
To be honest, I've not seen any pics of Phil even wearing feminine clothing since he stopped cosplaying as Sakura Haruno. He just dyes his hair pink and calls it a day.
With Phil's physique, lack of hygiene, and overall spud-like appearance, dyeing his hair pink doesn't make him look like a woman, but instead like an emo Nosferatu in a Vampire: The Masquerade game.