As far as I understand it...they actually do own these characters. From what little I remember reading about this, Archie never actually had any of these writers sign a work-for-hire contract. Without that, technically all these comic-only characters from that era are the rightful property of their creators...unless they are deemed derivative. Of course, somehow, "evil Sonic" was deemed not derivative and I guess Penders has a right to him, so who even knows.
Common sense and legal right are often in direct conflict with each other.
Of course, if this gets the comic killed off...or even if they decide to make the Mega Drive books the new "real" continuity...I'm going to be mad. Ian just got done trying to rebuild this universe, it be a shame to let all that just be a waste.
They did have them sign work-for-hire contracts. It's just that those contracts were thrown out by a warehouse worker while in storage, and the photocopies that Archie has aren't eligible in court.