It's "like" them in that it's similar to them. I would never have guessed that this would have been lost on somebody. the age of one relative to the other doesn't make them any less similar.
Also, the Guardians of the Galaxy, as they exist now, have been around since 2008. So you're not only being a pedant, but your pedantry is actually incorrect. Even going by your chronology, ME2 is "like" Guardians of the Galaxy since it released after them.
This is starting to be one of those "how to you define 'is'" conversations, isn't it?
I think the point of the whole GotG thing is that it wasn't major public consciousness until the movie, since it was pretty much a D lineup team and only the real hard core knew about. That changed of course with the movie.
That being said, since it WAS out prior to ME2 and could have been read by the devs, well, anything is possible.
Honestly, as long as they stay within some lines of the lore, and then introduce the new stuff in terms of that viewpoint we should be fine.
Nothing is created in a vacuum. Even IF the devs don't consciously use GotG or Interstellar, if they've seen them or read the comic or whatever it's going to be in the back of their heads.
For me, I like the mix. It feels like B5 to me, which is a very good thing in my opinion. And note I say it feels like. It isn't B5 nor is it trying to be, but I get the same vibe, and it's one that drew me to both series.
YMMV of course, but hey.