Are there specific ROS1 fusions/mutations that confer sensitivity or resistance to therapy to help guide treatment selection in first line or at progression?  

So far, the fusion partner with ROS1 fusions does not seem to predict response to ROS1 TKIs.

G2032R is a relatively common mutation. Repotrectinib is active against this mutation. Beyond this mutation, I'm not aware of others. 

There are several ROS1 solvent front and gatekeeper mutations that lead to resistance to crizotinib. Many of them may retain sensitivity to newer investigational agents such as repotrectinib.