Regarding the Space Wolves and their relationship with the Inquisition; I think chances are that although they are happy to tell an Inquisitor to p*ss off, they're unlikely to tell the Inquisition as a whole to p*ss off.
With the former, they'd be faced with one annoyed Inquisitor who, despite his authority, would be pretty much powerless to take action against a chapter as famous as the SW. The Inquisitor wouldn't have enough personal forces to take on the SW and if he tried to requisition more for a campaign against them, chances are other Inquisitors would hear about it and put a stop to him.
With the latter, well it's hard to know how the SW even could tell the Inquisition as a whole to p*ss off - the Inquisition is not a monolithic organisation, so although they might annoy an individual Inquisitor or a Cell, Cabal, or even Conclave, that's not the same as teling the organisation to p*ss off.