With the Horn and how TV works I can virtually guarantee that they're working out how to not make the Heroes Dark via a massive striggle for it between Mat and Fain, and I think that might also be where Elayne bonds Birgitte. It just isn't going to make sense otherwise to wait 5 or 6 books'...
1. Moiraine's Oath is going to come into play. There is absolutely no reason for her to have sworn it specifically to Siuane as Amyrlin unless they're planning for Elaida's coup a lot earlier.
2. We'll meet Elaida at the same time as Elayne. My guess is Elaida is going to be acting as...