The information I have to hand, which comes from the Canadian Ministry of Defence is that a separate Ministry of Defence for Air was formed in May 1940, with a new Air Council at the same time to advise the Minister. The new Women's Auxiliary Air Force was formed, with over 17,000 serving at home and abroad, it later being renamed the RCAF WD.
The research I have done finds that the Canadian Government was grated permission to enlist ladies into the RCAF on July 2nd 1941. February 1942 saw women integrated into the RCAF under the title RCAF Womens Division. So I guess any recruited before February 1942 were officially WAAF, after that RCAF WD.
The RCAF ladies uniform was originally a one piece dress, buttoned down the front and with a belt. Shoulder eagles were worn but it was not popular, so the standard two piece was introduced, probably with the introduction of the RCAF WD. I have some photos of one and will try and post them in the next day or so.