Yep. A denial, imho, is no biggie.
Also yes.
I feel like this is a gray area that USCIS hasn’t caught up with, in the sense that they don’t seem to understand that a divorce decree takes time to produce. Moreover, some States have a trial separation prior to.
What I would have done is to inform them of the divorce proceedings and wait for the RFE for the DD. If I have it hand, fine. If not, I’d have written an affidavit explaining that the decree is not ready. And if they denied my 751, then I can always reapply.
I prefer dealing with a denial than with a pesky officer at the N400 interview.
That being said, OP, you’re probably fine.