Of course IDMF grunts count towards Wolfpack support, there are no Wolfpack grunts. Even Wolfbairn and Wolfbane Commandos are IDMF units, therefore if IDMF units wouldn't qualify you for Wolfpack support then it would be impossible to field the Fenris or Necromower, as there are no Wolfpack grunts.
Its the same with Bauhaus and the Homebuilder Protectorate and the Elector Dukes.