As the assets are still in flux at this stage of the game, there's still quite a bit to be changed before we lock in anything with assets. I'll also note, because there appears to be some misinformation here, that the norm is typically not to credit the authors of assets from storefronts.
The license on most storefronts is for the asset as a clean piece of work, without any artist name attached. In some cases this is because it's not purely their work that has been purchased, and the artist may be using art they purchased from somebody else as a basis for their work or had others contribute to the work they created or the work was done as a collaboration. In other cases it's because their name has not been properly attached to the work. As well, in some legal jurisdictions it can raise issues to credit individuals without their express permission.
All that said, we will be looking at crediting any people we can for their asset work that is used in Dead Matter at a later date - the current credits provided with the Closed Alpha are not complete by any stretch of the imagination, and will be seeing a revamp at the time of the launch of the EA release of the game.