When it comes to surviving in a post apocalyptic environment the three people I would want to team up with would be:
I would choose green arrow because he is a survivor. He was stranded on an island for years and came back stronger and smarter then ever. He has taken down some big names villains in dc and all so the right eye of the most deadly assassins death stroke. He is trained in many different fighting styles and an artist with his bow . He is a very strategic person and I feel he'd be a good partner to have in a post apocalyptic environment.
My next pick would be:
I mean who wouldn't pick wolverine he is a pear badass. He can't die and he's a fighter no doubt as well as mean and brutally honest so he will help keep focus and on task. As well his claws would be the ultimate survival tool I mean the can cut anything the don't brake or ever dull.I feel like he just explains him self!
And my last but not least choice would be:
Vision I feel like would be the best pick because he nearly indestructible thanks to the vibrainium and extremely powerful thanks to the infinity stone, I mean like his powers are endless. He is considered pure and honorable to lift thors harmmer. Plus he's an android who's purpus is to ensure the survival of humanity, so I feel he'd be a great leader who could potentially save humanity.
So there you have it those are the three heroes I would want have on my team to ensure survival.