May sound a bit strange but that rust still looks a bit green. On my first pass, I'd go with oil and 0000 steel wool. Regarless, some of your blueing will be removed. At this point, you will get a better idea of how deep it has gone and perhaps, not taken root.
Do not soak it in rust remover as you will probably remove more than you really want. I'd live with the results and reblueing is always an option. ...
Be Safe !!