Is it at all possible to use EZ scenery library objects in RWY12? I know the XML files are different but is it possible to use them at all if so what do I need to do?

Yes it should be. The objects in an EZ Scenery Library are the same as for Rwy12. you would need to create an appropriate XML file for RWY12 from the library. You can do this by Hand I think or if you use Library Object Manager then it can read the library bgl and create an xml file for you. You would also need some thumnail images if you want to see them in RWY12