There are a lot of lead guitarists who don't like to focus on singing. I've especially noticed among YOUNG ones, that many don't sing at all(I believe when they're a monster guitar player, they want to focus strictly on their playing - and it is hard to play some really difficult licks while you're singing). That said, I have noticed that later in life, they finally start singing.
This whole "it takes two guys to replace Lindsey thing" is just hype. If they found the right guy, they wouldn't need two. But of course, these days, Christine barely plays anything, so they really benefit now from having two guitarists.
Then again, they're playing with tracks now, so who knows, they could probably pull it off with a hologram.
