- Yes. You can see other considerations at "reset hard on git push".
- You can test the name of the branch when receiving the commits.
branch=$(git rev-parse --symbolic --abbrev-ref $refname)See also "Writing a git post-receive hook to deal with a specific branch"
- a rsync is usually recommended for live server (where git isn't necessary): it will update only what has changed.
If you have git on live server, then various approaches are described in "Git for Websites / post-receive / Separation of Test and Production Sites"
Regarding deployment, as seen in "Deploy with rsync(or svn, git, cvs) and ignore inconsistent state during deployment?", deploying (even everything) in a separate directory and symlink the prod instance to that directory is a nice way of avoiding inconsistencies during deployment, and to facilitate rollback (symlink back to the previous live directory) in case of trouble.