1. Yes,usually where the 2 parts join,needs re sealing.search chris fix on you tube.

2. In my signature there's a link to a diy - gettin ya gaps right.u should be able re position ya taillights to by undoing the nuts at rear.

3. I would search you tube for a fix.might not be able to separate.

Normal wear and tear. 9 months might be a bit long to go back.

never had the taillight peeling inside issue. ..