So, you don't think your NIW petition case is strong, but you just want to get EAD for them temporarily (before they become Canadian citizens)anyway? If that's what your question is about, yes, you can do it. Just keep YOUR non-immigrant status valid at all time so you don't lose legal status when I-140/485 denied.
One more thing, 來美國開診所, she got licensure and graduate medical program (residency) problem need to solve first. 或者到大學任教, if for post-doc, it's OK. But universities don't like to hire temp EAD holder for formal faculty positions, they prefer H1B or EAD under EB1 which they are sponsoring. So temp EAD won't help her much for the desired jobs you listed.
As for the article, it is either written before early 2003, or the author has not gotten updated information since late 2003. Several BCIS/USCIS memos have clarified/sovled the author's concerns since then.