Breakfast around Yonge/Finch
i live in the area and as far as i know, there's really little choice for sit down, full-service breakfast.
it's possible that john anderson's does a breakfast, and perhaps the basement food court in the basement of the xerox (pink) tower at yonge/finch.
aries cafe will have coffee/tea and some sweet pastry/cake options, but i'm not sure they open that early. i have no idea what time cafe buda or le monde open.
there's a cute place across the street from the last two, called capriccio. however, if open early, i believe your options would be limited to tea/coffee, cake, pastries, and cookies.
finally, it's a sure bet that novotel (beside/inside north york centre) has breakfast.