Thanks to Chris Mawson, from Power-Up Gaming, Titanfall’s Season Pass seems to be free for everyone on the Xbox store. I suggest reaching the Xbox store via the link below:
There you will see the Season Pass and Add-on DLC’s listed for free for anyone to grab. The Xbox 360 version however must be D/L individually. I have verified this and again thank Chris for the heads up. The original story can be found below.