When Ash was in the hallways of his old high school, he remarked that he met his first Linda there. The Linda he was referring to was Linda Emory (nee Bates) who was featured in the show's second season. Additionally, this reference serves as a joke because throughout the original film trilogy, Ash's girlfriend Linda was portrayed by three different actresses.
One of the symbols on Pablo's stomach (on his right side) looks suspiciously like the Triforce from the Legend of Zelda game series.
When Dalton says "One for all and all for one" he is quoting the motto of Alexandre Dumas' The Three Musketeers.