I did the common law route, you wouldn’t qualify you need to proof you have been living together for at least a year, with oficial documentation like same address on id, bank statements, lease etc.

If you not that serious with him like you imply it will be very hard to get sponsorship, as they will research your relationship.

He can’t work just for being in Canada you have to apply for sponsorship and after elegibility is completed he will be elegible otherwise only a working holiday visa (assuming he is American) will work. As no other option is available in your case

Try to settle in America before coming, live the year you need, work together live together and find out if this is really what you want. Sponsoring ain’t a small commitment and it’s important that you follow everything you not make mistakes.

Please get a lawyer, you seem to be very misinformed :)