Requirements to make an aran?

Anyone knows them? like, you create one right away, need some quest involved like for cygnuses, or you need a begginer to reach lvl 10 and job change?

Create one right away using the race select screen.

All you need is a free slot, which you get one when they come out.

Wait, we're getting a new slot? sweet

Yeah, same thing as with Cygnus, everyone gets one free slot.

Silly question, but does that mean that max char slots will be 18 (6 Adventurers, 6 Cygnus, 6 Aran), or does the Aran count as one of the others?

MSEA increased char slots from 12-15. I assume we will get the same.

Silly question, but does that mean that max char slots will be 18 (6 Adventurers, 6 Cygnus, 6 Aran), or does the Aran count as one of the others?

Uh.. what.

A character is a character, no matter what it is.
You have 4 slots to work with, 5 after Aran (assuming no character slots have been bought). There is a max of 12 characters right now, presumably 15 after Aran. Therefore you could theoretically have 15 Adventurers, or 15 Cygnuses, or 15 Arans on one server on one account. The combination doesn't matter.

Silly question, but does that mean that max char slots will be 18 (6 Adventurers, 6 Cygnus, 6 Aran), or does the Aran count as one of the others?

No, the free slots act like if you bought them, the max is 15. Maybe after KMS releases that "new class" it will be 18 though.