Not to get sideways with CD......
But the reg you qouted specifically 4 (b)(i) allows an air carrier to use its own approved De-ice manual if it meets the standard. USA Icing regs under 121 and 135 are just about verbat. to the Canadian ones.
Personally I think a proper Captain could have nipped this whole thing in the bud.
A good rule: If any one on the crew (be it F/O, F/E, or cabin) ain't happy with the proposed parameters of the flight or the Aircraft...we ain't going.
We all go or no one goes.
Bet your sweet butt your all gonna get to the crash site at the same time.