This is how I would do it, for each different character type (no gun, with gun etc.) give them all the same family. Then replace all your coding for charlie with family object, which will make it so that all of the character sprites are doing the same thing.
like this (i replaced 'charlie' with the family 'friedly'):
then you just need some events (maybe a global variable)
when character = 0 then make charlie visible and charlie gun invisible
character = 1 make charlie gun visible and charlie invisible
that's just a way to do it I guess.