> Would Cruise have been accepted to Ycombinator at all if it had just been Kyle applying?

Yes, without a doubt. He's previously YC by way of Justin.tv / Socialcam / Twitch. If you're good enough to go through YC once and have a track record of success you're a shoe-in for your next venture.

Realistically Kyle would have been accepted to YC without any idea and he would have been wildly successful with Cruise even without YC.