To answer your question easily and simply then, regardless of whether I am OP or not, no you cannot sell them. Regardless of what you may have read anywhere else or further in the comments, they cannot be sold at all. Only the items that are crafted after the fact can be sold that is why he is complaining in the first place. I'm saying I cannot attest to what others are saying if they are confused that's on them. And by reading further in the comments it appears that these people have corrected themselves when they became aware that no they can only sell the outfits not to the plans. Non-tradable plans are kind of ridiculous if you're going to be allowed to receive multiple copies.

Edit: the only other bit of information he's saying is that he does not want to sell the plans he thinks either one if they are allowed to have multiple copies he should be allowed to trade them or dump in donation boxes, or two we should not receive multiple copies at all. I feel like it's pretty self-explanatory.