This is how and who I would use to infiltrate the famous Area 51.
So as my fighter I choose Deathstroke. With his heavy weaponry he would make the perfect candidate for this mission. Agile, fast, can use 90% of his brain, and can even move so fast that Superman can't spot him. Having military experience Deathstroke could and would know how their base works and could handle anything they throw at us.
Muscle: The Hulk
For muscle he have the Hulk. No doubt Area 51 has some heavy weapons on their side and the Hulk is perfect for taking those big guns out. Since Hulk is so use to the military going after him he would also have experience getting through all their defenses. One thunder clap should do the job.
Damage taker: Deadpool
And finally we have the damage taker. While Hulk is taking out the tanks and what not, Deadpool will be the one getting inside the actual base. With his healing factor he could easily run through and get inside. Also with his teleportation he could get there and get the hidden government secrets in no time. Not to mention Deadpools cockiness and confidence.
So yeah that's my mission and my team to get it done! Think my team is good enough? Let me know below!