I'm assuming OP is in Canada, which probably changes what advice to give and which loans are available. There have been other people here on the forum that swear they would never be a landlord in Canada due to very favorable tenant laws.
OP-- how many rental properties do you currently own and who do you rent to? I live in a college town where rooms do get rented individually and I'm also a landlord, but I generally stay away from traditional student rental situations.
I don't understand how you estimate the expenses of the single family homes to be only $9,300 per year. I would imagine the mortgage would be at least $1,000 per month, plus all your other costs. Can you elaborate a bit more?
Who is doing the work in these houses? How much does it cost in labor and materials to do the renovation? It doesn't sound like you're including that in the calculation here. What constitutes a 'legal suite'? I wonder what kind of house you're buying that you can fit 6 of these into one.
edited to add--- I read through OP's previous postings a little. It sounds like you have 20 properties--- some single family, an apartment building, a commercial building. It seems like you shouldn't need any advice from us, but it also sounds like you might not be great at doing financial analysis or at least explain it very well here.
Also, do your zoning laws allow you to cram all these bedrooms and unrelated people together? In my college town, there is an ordinance that generally limits 3 unrelated people in the same house.