I don't know who the mystery seducer is, but the angry mob seems to believe it was Fanning.
There are only 3 other names I'm willing to consider.
1. TP, for obvious reasons.
2. Fitz. Look how often he uses the word "my". Could easily see him pitching ownership of GPC to some sloppy drunk porker at a KC hotel bar. Once she awoke from her roofie-induced slumber, the last thing she could remember was him saying something like "you may recognize me from my TV show or my K-State website, go... go-something".
3. King Winters. A newly-crowned Wintz was a little power-drunk one night and exaggerated his role here. I don't think TBL is giving him shuttle rides to KC though.
All that said, look how defensive Fanning is. Clearly it's him.