I'm in Alberta and with an agency. With the agency you're allowed up yo 6 (including your own). From what I understand you can have more than 6 if you're private, but I've heard different things from different people (official documents on this are murky, I haven't found anything that outright states a limit on # of kids).

With an agency you are limited to 2 under 2, 3 under 3. It can be difficult to fill the over 3 spots if you don't drive as a lot of them are in preschool, kindergarten. There aren't ratio rules with private.

The agency can refer people to you, though you might have more competition than with word of mouth.

My agency fees are minimal ($50/month), but in AB you can get wage top-up if you are with an accredited agency and are qualified (everything from working in a daycare/with children to any degree involving children or education). It's $2.21-6.62/per hour you are open with a child under school age. It doesn't seem like much but can add up quickly (my full months are ~$1200 on top of the monthly fee each child pays).

As for your list, I don't have any of the first 3. But I have the agency to cover my butt in case something happens.