No and No.
Romney has flip flopped too many times. Something his GOP opponents are going to exploit.
Also, the GOP base of the deep south would never vote for a Mormon. No matter how much they may hate Obama, they'd never vote for someone who they believe belongs to a cult. A cult which claims to be Christian but isn't (I'm just repeating what they believe), marries multiple wives, doesn't believe in the Bible, have their own Bible, believe they are the only (true) church, and don't believe we're fully saved by mere faith...
In addition to all of this, Romney belongs to a church that has a living and breathing leadership which claims to receive direct revelation from God. So are you voting Romney into the white house or President Thomas Monson?
Mormons and evangelicals have a history. So I wouldn't even be surprised if things got heated to see someone taking a cheap shot and bringing up the Mountain Meadows Massacre just to create fear and hatred.
Again, I'm not saying that I believe this way. I myself am Mormon. But I know what Evangelicals think of Mormons and I know what Mormons think of them.
I've seen this movie before and know how it ends. Romney has no chance. If Obama has a huge scandal and the GOP wins in 2012, you're probably looking more at the possibility of Palin as the new President than Romney.