Hi, I basically wrote about job opportunities, why I liked Ontario and some vague future plans. I don't think it's necessary to apply to any company, at least I didn't. I personally wouldn't follow any sample statement of interest too closely, since I felt that most of the samples I managed to find online were a bit generic and gives off a copypasta feel, just my personal opinion tho. Since you have 2 cousins studying in Toronto, maybe you can talk about how their experience in Toronto influenced your decision, or how their presence could help you settle in Toronto/nearby. I believe this is technically a tie to Ontario(family ties), so you might want to mention it in the "ties" section.
I also have an MS and a BS, and I only had a WES report for my MS, and everything was fine.