Who were the original poster-boys for the glam-oriented, hair metal, makeup wearing bands from la (and beyond) ?

There's no definitive answer to this question. Music critics and historians argue as to which band "invented" or popularized the "hair metal" and make up wearing LA heavy metal bands popular in the 1980s. Speaking as a published music critic and historian, I'd argue that the first hair metal band from LA to strike it back was, in fact, Van Halen. Van Halen, especially in the late 1970s and early 1980s (when David Lee Roth came on board as lead singer and "front man") began stylizing themselves with make up and "big hair" and began to sell hundreds of thousands of records (and eventually millions) over the late 1970s and inspired a number of "related" hard rock and hair metal bands (Bon Jovi, Motley Crue, etc).