Is it:
Urban
I'm thinking of a word you can spell on one hand.
5 letters in urban for 5 fingers on one hand.
If you add "e" or ɛ, it might describe the man who lived here:
An urbane man would live in that "courteous and refined [...] manner."
Add the sound of the world's favorite drink, and you'll find something often worn here:
Tea is the world's favourite drink (after water) and makes a T
sound (the letter t)
T + urban = Turban
Turbans are worn predominately by Sikhs and Muslims as a religious practice, and here is an image of the Muslim population.
Add the first 3 letters of this island's mechanical secret, and you'll find a common setting.
A sub, as in submarine. The island uses submarines as a weapon.
Sub + urban = suburban
The suburbs are common area [citation needed].
Add The One Who Originated and drink some with Coke.
I have no idea. I think "The One Who Originated" would be some religious reference, like Adam or Eve. I also think "Coke" refers to cocaine, rather than the famous carbonated non-alcoholic drink. (and, for completion's sake, it's definitely not coal coke), as you wouldn't drink something with another drink.
Also, should I unhide this as it's not the answer?
The hint:
> You want a hint to get you started?? The solution starts with you!
I think this means it is where I am. Since I am on the internet, I am in an urban area.
It may also mean "The solution starts with you" ("u"). Urban starts with "u" ("you").