Do I need to complete both sides of the story in dishonoured 2 before starting the DLC?

I’ve completed corvos side and I did enjoy it, but I’m not feeling playing through it all over again using Emily.

Is it important that i complete her side too? And what about the witches of dunwell? I’m thinking I should watch a YouTube video on that DLC because I felt a bit lost during DH2 story when they were involved.

Thanks.