I would seriously suggest Bil Dwyer for either Joker or Lock, although he'd prolly be better suited for the latter. Maybe Marc Summers for Joker. Ricci, who could you see hosting Lock, other than Ross King.
I don't know why, but the name Bill Weir keeps crossing my mind as a decent host, maybe not for any of these three projects, but anything in the future. He's one of the anchors on GMA, and from what I've seen, he seems to have a witty personality.
I'd also add Mark L. Walberg to the mix. He's proven himself as a respectable host. He needs one really big hit to establish himself.