I can't speak from experience against Pandora, having never played her, but for my Brewmaster force, I use Trixiebelle over any other Henchman. The ability to cheat fate on the initiative flip is important to ensure Ol' Brewy gets the initiative. Plus, she brings scheme running shenanigans with her "Presents? For Me?" as well as another way to apply poison with "Buy You a Drink?".