Interactive rebasing works fine for teasing apart commits as well (maybe slightly clumsier, but c'mon... it's git, it's _supposed_ to be a frustrating UX)
Even if you're on your own branch you can easily get a DAG after rebasing or resetting. The reflog keeps track of the history of all refs (ie. branch names) that you change. After you rebase your old commits are still there! It's actually quite hard to remove commits.
Trusting the reflog is key to becoming good at git.
I use interactive rebasing as the backdrop for teasing apart commits that are not the HEAD commit; it provides the navigation through the commits.
The cherry-pick operations that underpin rebase are not what actually does the teasing-apart, though; I do that with with git reset --interactive HEAD^ when I've landed using "edit" on the commit I want to separate.
