Excellent responses. Thank you. I would add that the O-1 and the E-2 are probably the best fits to do consulting work for multiple companies in the U.S. but the O-1 requires a relatively high level of achievement and the E-2 requires a "substantial" investment by (in this case) Canadian citizens (which can include investments by you) or Canadian-owned companies and a business plan that shows the hiring of U.S. workers (citizens and permanent residents) over time.
Yes, many U.S. employers, particularly those who don't want to lose out on good candidates, sponsor new hires for O-1 and E-2 visas. It's less about a "high level achievement" and really more about checking evidentiary boxes: an applicant must meet at least 3 of the listed O-1 criteria and very often for talented professionals at least 3 criteria are within reach.
