[Coldsaturn]

"I cannot tell if this is vaguely condescending, foreshadowing or just Rafe being a bit sassy."
With Raf it's usually all of them

Raf and hearts, that's important. Put a pin on it.

VAs:
omg yes, Raf's VA is everything. Out of all the characters, he's the one who emotes the most, and because of his personality he's allowed to go from silly to sassy to whiny to furious to cold to seductive to helpless. The range that he has, it's SO good /chef's kiss
Sylus is a second favorite, but in terms of what the voice actor does with him and how much leeway he's allowed is similar to Xavier. They have a baseline that they have to match (for Xavier it's soft and breathy, Raf it's that sing-song accent of his, Sylus you'll see), but it would be OOC to get them to voice something differently. Raf doesn't have that problem because he's an onion character.
Zayne I'll admit feels a bit flat to my ears, which adds to my preference for reading him rather than hearing him.

Oh and there are some Xavier cards which I think were recorded way back, because the voice is the same but it's not soft and breathy at all lol It's like they hadn't told the VA what to do yet. And I'm pretty sure I heard a couple of audios from Zayne where his voice was straight up another guy.