Let me take a slightly different slant on that question, by proposing a casting from our available heroes.
Clearly Elena is the red-headed dame with a problem that needs a good gumshoe to solve. She is the Flame Fatale of our crew.
The nickname for Richard also dovetails beautifully for the abbrecviated nickname for detective. So Slam Spade is our private ■■■■ on this case.
Renfield makes for a great Joel Cairo type. Given his role in Dracula, and the appropriate gangster nickname tie-in, we could do a lot worse for a name than Bugsy McFly for his skin.
Friar Tuck is the spit and image of Sydney Greenstreet. So he’s a shoo-in for the Kasper Gutman role. I’m thinking he’ll look perfectly ridiculous in a white suit with those green potions at his waist. And he does provide a mana boost. So, maybe Pots McMana?
Khagan seems like a reasonable fit for Lt. Dundy. I think he’ll do well in a red fedora and suit. Detective Khagan seems like just the guy to push Slam Spade around a bit.
Vivica works well, I think, in the Effie Perine role, as Slam’s loyal assistant. With her steno pad and ever-ready bottle of alcohol for our hero, I think I’m going with Vivian Lush for her skin name.
And last, but not least, we need someone to play Slam’s missing partner Miles Archer. Thorne is probably perfect for the role, because even after the buff, he’s literally nowhere to be found. Nevertheless he deserves a decent moniker. We’ll go with Cool Sword Luke.