I've kind of avoided this thread because the truth is...I don't know.
Surprisingly,I've never been heavy into Bolan where I've had any interest to study his history so I don't want to say Cooper was the first. (I enjoy a lot of Bolan's work but I was never obsessed with it)
As far as Coop though I know that besides being influenced by the Stones, Beatles,& Yardbirds the Alice Cooper band was just as influenced by TV,Movies, Musicals,& theold burlesque/vaudeville type shows & all of this added to their look & style.By 1967 they were wearing the shiny, glittery, & colorful pants along with experimenting with the make-up & long hair. They wanted to shock the world when they changed their name to Alice Cooper in hopes that the flower children of the 60's generation were going to expect a blonde female folk singer. I know the NY Dolls were influenced by early Cooper (I will say though that guitarist Johnny Thunders did like Marc Bolan as well & Keith Richards for all that matters). Alice did have a huge impact at Kiss in fact Gene & Paul have said that after attending a Cooper show is where they got the idea of the make-up (& yes when they did begin before they went with their familiar make-up they did try to go with a NY Dolls kind of look). Obviously the Dolls style wasn't working for Kiss so after seeing Cooper in Concert they though "What if we have 4 Alice Coopers onstage?".
Iggy was part of what influenced Bowie to get into the glam & that is why he became Ziggy.Iggy & Coop were terrorizing the Detroit scene in the late 60's