Your best off talking directly to the companies you are interested in working for. They will tell you what they actually require and/or look for. For example, unless they are specifically running whitewater trips they likely won't have any interest or need for any whitewater certification.
You might also want to look at university level programs in Outdoor Leadership like the one at Laurentian:
https://laurentian.ca/program/outdoor-a ... leadershipGenerally I support certifications, but I'm not impressed with the ORCKA Canoe Tripping ones and have yet to hear of a camp or organization that actually requires a Canoe Tripping Level 3. I know of one organization that wants volunteer trip leaders to have Canoe Tripping Level 2. I know of another that does not require any ORCKA certification.
Similarly, while first aid will be a minimum and wilderness first aid will often be desired or even required, wilderness first responder likely wouldn't be expected for most Ontario positions. On the other hand if you're looking at positions doing multi-week arctic trips then wilderness first responder may well be required.