I do not envy the hell you are about to go through.
My degree is in fashion design, and I worked for a menswear manufacturer for a number of years. We decided we wanted to do some manufacturing of our products at an excellent factory in Vancouver, BC, but, after more than a year of wrangling we were unable to find a way to make the deal work.
Essentially, when stuff crosses the border it is taxed according to what it might sell for in the future. If it is a "finished product", then it is taxed (heavily) according to the full retail price... because the country that made it also wants to make money on the thing they made. Except... you are wholesaling your products when you sell them to a US distributor... so you are paying tax on the retail price, but only getting paid the wholesale price. BIG out-of-pocket costs.
You can get around this by sending "pieces" across the border, and completing their assembly in the USA. (This is what the American car manufacturers generally do... they have their parts made in Brazil, Hungary, Japan, etc, bring them back to the USA, and assemble them... so.... "Made In America".)
But those pieces are going to be taxed as well, only at a lower rate because... of reasons. But still, you have to pay the tax before selling the items, so more out of pocket costs that do not guarantee your product will ever make it to US shelves.
And then there are limits on what textiles you can import to the USA (no bamboo or hemp), and the original source of your raw materials. (Friends from BC were bringing a bunch of wooden pallets to burn at an event here in the USA, but the pallets were not stamped with FSC certifications, so the wood could not be "imported" into the US because it wasn't FSC certified. Their art project never made it across the border.)
Good luck with your efforts. It is not going to be fun.