If #15 is fine and the root canal is stable, I would suggest to put
a crown on that individual
tooth. As for #13, I would always favor not treating
a tooth that's not needed. Plus, the life span of a bridge isn't that great so there's always the possibility that the bridge will fail and may jeopardize either #13, 15 or possibly both. I would suggest to try to deal with #14 individually with either an implant or a root canal.