I cannot find any information on the meaning of Zahaan, and it doesn't sound like any Arabic word I know of.
Arhaan, according to Mu`jam al-Buldaan, an encyclopedia of countries, is the name of a place, but it doesn't give any other information on it.
Nirvaan is a Farsi word that means translucent, transparent, solid, and is also the name of a place.
Mantashaa according to the Dehkhoda dictionary means a gnarled long piece of wood, such as a staff or stick.
I cannot find any information on Arzahan.
Arshaan is the ancient name of a Persian prince and means brave, courageous, doer of good deeds.
None of these are Islamic names, but where I've given the meaning, if you like it, then you can use it. As for the ones where I couldn't find the meaning, I cannot give an opinion on them.