edit The question boils down to \"Can git rebase be instructed to rebase tags, too?\" But an answer to the original question would also help.>
There is no built in way to do what you want using git. 'git rebase --tags' might be interesting but it does not exist.
If the commit messages are identical as you say then you could go through each tag in refs/tags, do:
'git log -1 --pretty=oneline '
Compare the commit message to the full list:
'git log --pretty=oneline '
If you find a match (and the SHA1 hash is different) then do:
'git tag --force '