Re: What if Kane didn't work out?
Brian Lee was in DOA at the time, as Chainz. Like you say though, he was a little on the short side to pull off the character. One of the major things that made Kane so impressive was that he stood taller than Undertaker.
Lee was part of WWE as Chainz, but if he was playing Kane, he'd be under a mask anyways, so don't see how it would have been any prob to do so.
WWE also had Kurrgan(7 feet tall) who could have fit the role for Kane.