Neither is he wearing insignia of the orders in which he was invested as part of the installation ceremony that finished just before he went outside and inspected the guard as seen in the photo. The orders, decorations and medals that he is wearing in the photo were all received long before he was selected to become GG. The Canadian Forces Decoration was not (IIRC) one of the honours presented to him during the installation ceremony when he was also made Chancellor(s) of The Order of Canada (a promotion since he is already a Companion of the order). Order of Military Merit and Order of Merit of the Police Forces. I don't know the usual protocol for presentation of the CD to Governors-General, but my expectation is it will likely be presented to him by the CDS. Hopefully, it won't be during a coffee break as was the case when I received mine.
As for individuals on that parade being out of dress . . . it appears that the somewhat rotund Air Force NCM just to the left of the GG does not have his CD court mounted. Also, while he is not visible in the above photo, the guard commander (a LCdr) was wearing the black leather CF sword belt outside his naval uniform. I haven't been able to find any photos of that officer but recall it from watching the ceremony on TV.