Having a manufacturing site in the US is a must once they get to the point of having multiple drugs out in the market. They won't be able to supply the market efficiently going over the boarders. And, it's not cheap transporting long distances.
Having a third party manufacturing your product risk having your technology stolen, and your cost becomes higher too. Assuming MNK start marketing all three ANDAs in both Canada and US in the future, IPCI will need additional facility. Especially for drugs that can't be imported into US like Rexista.
I am not sure how they are going to partner Rexista. They have to show the partner how to manufacture Rexista using nPPPODS. Manufacturing control looks like a lengthy process with FDA to gain final approval too.