This match up is fairly easy if you land your CC properly. You'll want to kill the Death Knight here and control the Shaman. If the Tremor Totem is destroyed while the Shaman is in one form of CC by either your Mage or Warlock the match will play out quite easily. From there you have plenty of time to drop the Death Knight/reapply CC safely without fear of totems breaking it.

As the Warlock a helpful hint would be to save your Demonic Circle portal for when you're Death Gripped. Death Coil can be used both defensively and offensively depending on how the match is playing out. If the Warlock is at a safe distance from the Death Knight you can look to try and get the gib prior to his use of Anti-Magic Shell. If hes at a threatening distance it's best to use it defensively as a peel.

Mage PoV:

Not too hard of a fight. Deep Freeze the Death Knight when the fight starts, help your Warlock get Tremor Totem, then just kill the Death Knight while CCing the Shaman. Try to anticipate the trinket/NS heal so you can Counterspell him before he gets it off, then Sheep him.

Spellsteal Earth Shield and Bloodlust if they get a chance to use it