According to PAD regarding the creation of New Frontier: "The basic concept was John Ordover's, as was the notion of using several already existing characters
. I fleshed out the concept and created the original characters." Source
But the choices
of Shelby, Selar and Lefler were PAD's, IIRC. He wanted
to use them because he personally liked the actresses and it had to be cleared with Paramount that the canon series was not planning to re-use them.
That is because the artist was working from reference photos and had nothing to do with PAD.
No, it's because PAD had been annoyed with depictions of his NF characters on the book covers and he personally worked with the comic artists and approved the art on both NF stories.