From the moment you distribute your Myth creations in any way (ie the Mill) they are the property of Bungie, which now means they are all currently the property of Take 2. Not their authors.
If Take 2 were tell Clem that they wanted those files, he would have to give them over or get his ass sued.
Thing is, those files are available elsewhere. In fact, if you talk to Infininight, he has a list of what was on the Mill and is trying to gather them all together.
So a start from scratch isn't needed. In fact, Flash, do you have any more info on this project of yours?