rebase and unmerged files

I tried to cleanup commit mistake and use rebase -i. It stopped and sha1 and generated a list of unmerge files. My intention was to use the version in sha1 but with some editing. Since all those unmerge files contained unresolved conflict delineated by

<<<<<< HEAD ======= sha1

I have to manually type commands such as git checkout sha1 -- file1 to get the version I wanted for further editing. Is there any easier method that can automating checkout all those sha1 version of the unmerged files.

Also, for git-commit during rebase, should I use git commit --amend or just git commit