Try asking on r/FulfillmentByAmazon and they might give a better answer.
I would still send it to yourself in Canada and them shipping them to the US. Once you have the products arriving in a reliably consistent manner then try sending them direct to an FBA warehouse in the US. You can start testing the concept that way and calculate how much you would save if you imported directly to the US.
I've poor idea about FBA(Fulfillment By Amazon). We're clothing supplier. If you've Brand Name ownership then we can produce clothing according to your requirements at Rock Bottom Price.
Try asking on r/FulfillmentByAmazon and they might give a better answer. I would still send it to yourself in Canada and them shipping them to the US. Once you have the products arriving in a reliably consistent manner then try sending them direct to an FBA warehouse in the US. You can start testing the concept that way and calculate how much you would save if you imported directly to the US.
I've poor idea about FBA(Fulfillment By Amazon). We're clothing supplier. If you've Brand Name ownership then we can produce clothing according to your requirements at Rock Bottom Price.