Kim here with Bruce Wayne, who definitely knows Wally. He ran a DNA test on Bart for Barry when the kid first showed up. Bart... concerns him.
Pepper Potts - they probably don't know each other, but redhead solidarity, yo!
Lois Lane-Kent - might have met, depending on how well he knows Clark. She and Clark have been married three years now. Clark knows Barry pretty well. Lois is way more level-headed about Bart and Kara dating than Clark is.