I contacted Greg Slayden who sent me this response:
I am pretty sure that Jack Bennett is still the only completer of the 13 Canada province/territory high points. However, his son Tom Bennett has done 12, only missing the Nunavut HP, Barbeau Peak on Ellesmere Island. To complete the list, Tom is planning a trip up there for this coming June, and if successful, he would become the second person. He is looking for those with the time and the money to join him. I accompanied Jack to Barbeau in 1998 and it was a fantastic trip--a real Arctic wilderness adventure. I recommend it heartily if you are considering it.
There is a group of Canadians planning to do the all 13 highpoints, and they have done Logan, but I don't think they are near completion:
Even though there are only 12 peaks on the Canadian province/territory high point list (QC-NL are a virtual two-fer),
half of those require serious expeditions and/or mountaineering skill. Mount Logan is not even the hardest.