I don't get the Haley popularity. Her politics aren't Trumpy, she says stuff like "everyone knows Russia meddled in our elections", which I suspect isn't that popular with Republicans (and Democrats won't care in a few years), and won't endear her to Trump. Also, there's the fact that Pence would be a sitting Vice President, and will probably run. Unlike Cheney or Biden, he isn't super-old and could easily follow the path of previous Vice Presidents, like Bush Senior or Gore. Finally there's the fact that Haley endorsed Marco Rubio in the South Carolina primary, and he came in third.
I was very critical of her appointment to begin with. She's a snake in the henhouse.