I think the games would go in order as the movies release.
Battlefront= 4-6
Battlefront 2= 1-3
Battlefront 3= 7-9
It depends.
There are 3 unknown variables dictating the release date of Battlefront, and subsequent content.
1
ice La's new game. What is it and when will it release? Considering the familiarity with Frostbite it's not unreasonable to assume a 2 year turnaround. Fall 17, likely another Battlefield spinoff.
2: Are there any other Star Wars games in production? Seems like a no brainer, but I think people are overestimating the number of studios working on Star Wars games. We only have 2 rumored, to my knowledge, Battlefront and Star Wars Visceral. Imo Visceral is releasing next to SW8, Late Spring '17. Without any other games coming EA could push BF2 towards SW9, Spring '19.
3: When is TitanFall 2 releasing? I don't think this one matters as much, as EA has said in the past that they think this time can coexist in a line up. This could be an interesting wildcard though. If it looks good enough it could push things back. Spring 17.
I think they'll give Dice a year break(4 games in 3 years is kind of insane).
So.
Bf - Fall 2015
Bf5 - Nov 2016
TitanFall 2- Feb/March 2017
VSW- April/May 2017
Dice LA - Nov 2017
Battlefront 2 - March-May 2019
Bf6 - Nov 2020
If Battlefront 2 releases next to Epi9 it will undoubtedly be NT focused.