I have an Ontario Business License (business number).

Not sure about your tax question as I have a tax lady who does it for me.

No you don't need a business bank account, when you have a business number. You don't even need a separate account or do separated billing.

I use my business number on my receipts. I also have a line on them that states: • Providers SIN number will be provided to Canada Revenue upon request, by Canada Revenue.

Yes you can all yourself a daycare, just not a licensed daycare, unless you join an agency. You can even call yourself a centre, just not a licensed centre, unless you join an agency. (I have spoken to the MOE about this)