Are Samatha and Vipassana mentioned in the Pali Canon as different styles/techniques of meditation?
Yes, but not as seperat for the taught purpose:


  "These two qualities have a share in clear knowing. Which two? Tranquillity (samatha) &amp; insight (vipassana)... A Share in Clear Knowing


(Not given for trade, exchange, stacks or entertainment but to come out of this wheel)