Quick one: Possessive of mujahideen (plural) in English text

Singular: mujahideen

Singular possessive: mujahideen’s

Plural: mujahideen?

Plural possessive: mujahideen’s?

What say ye?

According to m-w.com, mujahedeen is already plural, so I don’t see why the possessive would be any more complicated than mujahedeen’s.

never mind

Thanks!

Next question:

Is is a proper noun (for the anti-Soviet resistance in Afghanistan)? So, capitalized?

Not according to m-w.com or Merriam-Webster’s Collegiate, which is what I happen to have at hand. Neither source lists it as a proper noun. It’s simply the plural form of the Arabic word that means “one who wages Jihad.”

I prefer Fremen, myself, but that never really caught on, I guess.

Singular: mujahid (مجاهد, )