Hey @ZX_THX!
If you are going to be using identical methodology over several games, it may be best to simply migrate the assets as you stated in your second paragraph rather than recreate your entire blueprint over again by trying to copy nodes. If the base functionality of your games is exactly or near the same, you could also duplicate your project and use that as the base framework you add on to.
As for your second problem, I am not sure. Did you combine the meshes or add them to a group in your level?