Dividing paper after Reject & Resubmit decision
This is common for very novel, high impact findings, particularly when the issues are complex and have both theory and application. What I’ve seen work is a shorter theoretical work submitted to a high impact journal that touches on application (often, the work references this ‘submitted’ or ‘in preparation’ work). The longer work is then submitted to a lower impact journal, sometimes just because the page limitations are more forgiving. 

This of course works best when you can tell two separate but related stories that feel complete on their own. If you and your coauthors feel like such separation is forced, it may weaken rather than strengthen the effort. 

I’d say your #1 might be unlikely unless you get buy-in through discussion with the journal. #3 may not do your work justice. I’d lobby for #2 based on the limited information available.