When I saw the quotes that I linked to from People, my first thought was that the designer doesn't understand the U.S. legal system very well.
He wants the Gosselin kids as models? Who has the right to decide that?
Right now, both Jon and Kate have that right jointly but not separately. That may, in fact, be a reason that Kate put her own plans for a clothing line on hold -- because she can't just use the kids as her models if she and Jon have shared decision-making.
Similarly, Jon can't commit the kids to the clothing line either.
And Jon's rationale for naming Hallie as a co-designer has to be to get himself some money that's not encumbered by his responsibilities to the kids. But why would Kate (or a children's guardian) ever acquiesce in that?
All in all, this was not the kind of thing that you do publicly if you have any sense. Not at this stage, at least.
Apparently Jon doesn't. Have any sense, that is.