Is there a difference between Hokkien and 闽南话？ Minnan or Taiwanese?

Yes, but differences are really subtle. Teddy speaks Median Hokkien but I could talk to him in Taiwanese. Each area has it's own twist to Hokkien but your can still basically communicate. Most of the conversation was trying to figure out differences. Really fun session as many Mandarin and Cantonese speakers in the room and the all could understand the slight variations.