It's actually against the terms of use of Cosmos to redistribute the models in scenes, and since some are provided to us under specific licenses for use in Cosmos, it would be very hard to validate which ones might be "kind of ok" and which not. The usual story when it come to sharing scenes :)
Fear not though, for future Academy chapters we have painstakingly built / will build scenes from scratch so that all models, textures, etc. are ones that can be redistributed, because we made them.
PS the Cosmos idea would only work if the scene could contain a placeholder that "pointed to" Cosmos content to download, but that isn't possible.