Round here, using the word 'lads' to refer to your male friends became popular in about the mid 90's. It was around the same time that Loaded magazine started using the term a lot and was more for referring to short-haired rebelling collar-up young men, out drinking lager and generally being rowdy. Think of lads in Essex in their XR3i, blue jeans and white Reebok Classics and you've just pictured the first generation 'lads'. Then the phrase 'lad mags' was coined to describe sorts of magazines like Loaded, FHM, etc.
Not heard of banter being used other than for larking around, comedy banter between people etc, but that phrase has been used for years surely?