Well, her editor (I think Fiona Crosby, no longer at Penguin) will definitely have worked on edits with her, including structural ones. Her agent is also likely to have done a round, perhaps more than one, of edits, with RW, before sending the MS out to editors. We can’t know what the edits changed unless we see drafts.
I can’t actually find the actual text of the statement made by PRH (does anyone have a link?), but from what I remember it was much what you’d expect, saying they’d bought it because of its ‘story of hope’, and found it ‘moving and inspiring’, like many readers, that the author had signed a contract testifying to its factual accuracy, that they’d done their due diligence and it had had a legal read, that no one had raised any issues before The Observer approached them. And that as it was their priority to support their author, they’d decided to postpone the publication of OWH in conjunction with RW, because of her distress at the allegations.
I think that’s a fairly standard ass-covering statement, tbh. It doesn’t say the allegations are untrue (how could it?), and acknowledges the impossibility of RW putting a new book out there when there are significant problems with her credibility. However, she’s still their author. For now, anyway.