Wired has an interview up with Charlie Grandy, the credited creator and writer and here's a snippet

Velma began three or four years ago when Kaling was invited to peruse the Warner Bros. catalog and unearthed a latent affinity with Velma. “She had seen herself in that character growing up,” Grandy says. As he and Kaling developed the show, they were always aware of Velma’s online legacy and “really wanted to honor that.”"

I think it's patently false to say she's just an EP with no involvement