That is why I believe Scott Walker is Jeb Bush's biggest challenger for the nomination. If it comes down to a choice between them, I can tell you anyone who wants to win should support Bush because Walker is Romney 2.0
I don't know. After what happened with Todd Akin in 2012 the Republicans learned a lesson about avoiding candidates (particularly and perhaps unfairly, male candidates) from representing the Republican Party with extreme abortion positions. This, combined with the high likelihood of Clinton being the nominee, means that Scott Walker's abortion answer at the debate really dimmed his prospects for even being on the Republican ticket.
I'd say Rubio and Kasich are bigger threats to Bush than Walker is at this point.