Canadian? Gosh! "What all" and "who all" are an utterly standard distinction in my own speech. (Perhaps those W-NY/Ontarian connections mentioned above?) As for "where all", I was about to say not so much, but then in thinking it over I certainly would use it in things like "Where all did you look for it?" = "give me the exhaustive list so I don't duplicate your search effort!" or "Where all did you go?", etc.
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