directly in the doc. Is this a best practice for a content editing process?

Yes, because having an editor complete your content ensures it will read well to others.

Yes, a content editor's role is to make updates the way they see fit.

No$,$ the editor should have tracked changes which would have shown you where they would apply recommended edits.

No$,$ they should have set up a meeting to discuss each edit so you could apply them together.