Henry Covert has done some work on Agent Cooper's family tree, none of which involves the denizens of Riverdale.
"Linda Mason, wife to Vincent Benedict and grand-daughter of Perry Mason.
Marnie Mason, wife to Julius Benedict and grand-daughter of Perry Mason.
Marmaduke "Moose" Mason, nephew of Perry Mason."
None of these are mentioned in Dennis Power's research on Perry's genealogy.
No author has identified "Pauncho" Van Veelar with either Prof. Jarrod or the Inventor, and while I haven't read the Grandrith/Caliban books yet, a description of Pauncho on the Speculations in Bronze blog (see the list of links on the right hand side) indicates he doesn't really resemble Vincent Price.
"Mark McCain <The Virginian>, son of Lucas McCain."
No article identifies Mark with the Virginian.
"Léon Montana <Victor the Cleaner>, illegitimate and estranged son to Antonio "Tony" Montana by his wife Elvira Hancock; adopted later by Michel Poiccard
An opening caption at the beginning of De Palma's Scarface places it explicitly in the 1980s. Perhaps the author wishes us to believe it was an updated version of an event that occurred much earlier, or that The Professional takes place in the future. Or perhaps I'm giving them too much credit.
"Dean, great grandson of James Moriarty."
"Who's Going to Take Over the World When I'm Gone?" by Win Eckert identifies Dean as the Professor's great-nephew.
No one has identified Ben as a member of Josh Newton's family tree.
" (Dr.) <The Mandarin>, son of Fu Manchu; and father to Dr. Zin by the mother of Dr. Thomas Benton Quest."
The Mandarin, unlike Dr. No, has hands. I've already discussed the Fu Manchu connection. The Dr. Zin connection doesn't appear in any article.
" , great grand nephew of Vlad III Dracula, son of Doctor Septimus Pretorius by Countess Elizabeth Bathory."
This is at odds with Dennis Power's theory about the nature of Graf Orlok.