I am way a beginner when it comes to singing, I am interested in becoming a proficient atonal singer, But I am a bit confused when it comes to what are the most efficient things to practice for honing this particular skill-set. I want to audition for berklee in Boston, so I really need to beef up my chops if I am going to get in.
Take lessons.

If you're that serious about it, take lessons.

Much more valuable than a bunch of random tips you get from guys on the internet, at least half of whom don't really know what they're talking about.
I don't fully understand why Singing & Vocals even exists if every answer is just going to be "take lessons."

but ts, if you're a beginner like you say, you might be better off getting better at regular singing first. also, I don't know a lot about atonal singing, but will you need to know that kind of stuff for Berklee?
The thing is, if you don't know what you're doing, you can pick up a lot of bad habits if you just start applying things willy-nilly. You can hurt your voice, or do other things which will retard your development.

If he had just said, "Hey, I want to learn a few basics so I don't embarass myself at kareoke" I wouldn't say take lessons. (Well, I would ... but it'd be buried down pretty deep.)

But he wants to audition for Berklee. And he describes himself as a "way beginner." That means he almost certainly a) doesn't know what he's doing and b) is willing to invest time and energy into getting good.

So, yeah, lessons. It seems like an entirely appropriate recommendation for someone in his situation.
Quote by Jearl
I don't fully understand why Singing & Vocals even exists if every answer is just going to be "take lessons."

You obviously don't understand the importance of a good teacher that can hear the flaws in your voice and help correct them. Foolish comment is Foolish.

It is very difficult to become a truly proficient singer on your own.

OP: If you truly want to apply to Berklee, they are going to laugh you out of the college without a good proper background training.

Would expect to get into MIT if you hadn't ever attempted algebra?

Get a good teacher.
I have no advice to offer, but have googled atonal singing and atonal chant and found nothing. What the arse is it?

Assuming it isn't when children chant the alphabet or nursery rhymes without melody, which is what most of the results were for.