You only need five Republicans to cross over. My humble guess is that on the first guy up...they will find one or two Republicans to vote for the individual. By the second candidate in May...they might have five Republicans lined up. If you aren’t running in the 2016 or 2018 election....they might feel safe enough to vote and say they have no intention of running again.
The nomination has to get out of committee first, and the committee chairman has to schedule hearings. If he doesn’t, it doesn’t move. The Republicans can and should bottle this up hard.