I really dont think thats a good idea... i guess its your own story and you can do what you want but in twilight it says that once a vampire finds its partner theres no going back so theres no way that that could be possible for any of them (emmett, edward, or jasper.) But like I said its your story.
yes, i think you should break edward and bella up so ella and him can be together. there will be lots of drama tho between ella and bella, but it seems worth it ya kno? great story btw! update soon plz!