From my understanding, GotG is actually supposed to lead into TA2, which could be pretty cool if handled right. If the GotG show up on Earth just to warn The Avengers of Thanos impending arrival, then that would make me even happier 'cause I really want to see a full Avengers roster before they take on the likes of Thanos, meaning they really need Black Panther, The Vision and The Scarlet Witch.
As far as the GotG movie, I've heard rumors that they may also include NOVA in the storyline which, for me, would be the ULTIMATE in cool 'cause old Buckethead's been a fave of mine ever since his arrival back in 1976!!!