Tillis is up to 19% in the GOP primary; an improvement for him, but the toplines of this poll really don't reinforce any electability argument he would have.
None of the non-Tillis Republicans have under 70% unknowns.
Basically, the runoff will be Tillis vs. someone (and considering how unpopular the legislature is, I have a hunch that whatever Republican emerges from the runoff, no matter how obscure, would be a serious challenger to and possibly even favored against Tillis). Unfortunately, two of the biggest names in opposition are Greg Brannon (too economically right; might make for a good Senator from a safe, Western state, but not NC) and Mark Harris (too socially right).
Heather Grant sounds to me, from a quick read about her, like she would be a good nominee -- a young woman, has no link to the state legislature, with a background in the military (can't hurt) and in medicine (can keep the focus on Obamacare), she can be the generic Republican to Hagan's generic Democrat (and in NC 2014, generic congressional R probably beats generic congressional D). Flynn doesn't sound particularly bad either -- just that Grant may be the stronger candidate. What do you think, Miles? (I could easily be wrong; I hadn't heard of her until I saw her name in this poll write-up and then read a single article about her linked from Wikipedia).
From what I've researched Grant would probably be the best candidate for reasons you gave. Harris might be able to win too. But Brannon's darker ties are going to come up, and if Republicans nominate her, he's going to be closer to Todd Akin than Ted Cruz.
Bill Flynn is essentially a Cruz acolyte. Whatever Ted Cruz does, he will follow. I'd say he's less toxic than Tillis, but more toxic than Harris. In order of electability I'd rank them Grant-Harris-Flynn-Tillis-Brannon.
