I have never seen nor heard of a revolver airsoft pistol with non reusable shells. You should have no problems reusing them.
Yes.
No.
No, they can not, do not attempt to mix real ammunition in airsoft guns.
Simply refill them, yes.
Yes, airsoft shells are refillable, being made of hard plastic and a hole to insert bb's in.
Yes, once you shoot then, take out the cartridge and refill it the same way you loaded it up the first time.
yes
In all the airsoft revolvers I have seen each shell holds one bb for realism. Some also hold the gas to propel the bb, but most revolvers hold the gas in the handle.
yes
yes they are reusable
no
You have to take it apart