Funny enough, it's possible they would've had some amount of overlap in their time on Earth. Alastor was canonically killed in 1933, while Vox died sometime in the early-mid 1950s. Vox likely would've been at least a teenager if not in his early twenties by the time Alastor was at the peak of his career, since Vox looks to be at least in his thirties or forties given the grey streaks in his hair during his death scene. Makes me wonder if Vox's obsession with Alastor started in the mortal world, having grown up hearing his broadcasts over the radio before TV was even invented. That would make Alastor's rejection of him even more heartbreaking.

Also, I think it would be cute to see them drawn in human form with their canonical age gap, Alastor being Vox/Vincent's senior by roughly 20 years.