Which new 52 story arcs will help me be best prepared for starting the Rebirth stories?
I suppose it depends on which Rebirth books you intend to read. You really don’t have to read much from the N52 Superman books to follow the Rebirth Superman stories. Same with Tom King’s Batman: it’s far more connected to the pre-N52 comics than it is to anything from 2011-2016. Detective Comics, on the other hand, is directly connected to the Batman Eternal books from that era (which can be read without reading the main Batman titles of the New 52).
The New 52 Green Lantern under Robert Venditti flowed right into the Rebirth Hal Jordan and the Green Lantern Corps, also written by Robert Venditti; a seamless transition.