The timing of the Staal trade is... odd to say the least. He basically showed his hand to the rest of the league that he needs a center now - I highly doubt Buffalo would've passed on acquiring Staal for MoJo if it meant waiting another month while he traded Dumba.
Any GM that was paying attention already knew the Wild need centers, unless they really believed that Guerin acquired Bjugstad as his 2C for next year. It's semi-credible as a bluff, but other than that the need was already clear.
As for Staal, he turned in his protection list and was gone within 24 hours, so I strongly suspect that one was an attempt to shake up the locker room by trading a popular but soon-to-be-gone-anyway veteran leader. It's weird and bad as a hockey move, but I don't think it bears strongly on what happens with Dumba.