N-400 cannot be approved and will have to be withdrawn.
How long would divorce take?
If USCIS gives you 88 days to produce response to RFE, would divorce be final by then?
IMHO a possibly better strategy if you needed more time would have been:
1) File fresh I-751 based on divorce waiver
2) Wait for receipt
3) Withdraw both N-400 and old I-751
But of course, if divorce is quick, then you can try amending I-751 to divorce waiver.
More importantly, what does your lawyer say?
Supposedly, they should have some strategy for handling your case. That's why you pay them? And they can help you with writing statement and explaining what you need for interview etc. That's their job?
My lawyer told me which door to enter and button to press in elevator inside USCIS building prior to interview.