I can tell you that I don't believe any of the numbers at this point, because there are varying challenges with each of them.
My guess would be that there are significantly fewer than 10,000. About 235,000 people experience homelessness in Canada in a year, and there are 35,000 on any given night. Veterans Affairs has identified 2,500. I wouldn't be surprised if it was double that, but I don't think it would be a whole lot more.