Both those ideas feel so far-fetched to the point that it's idiotic. Colbert especially, since he hosts a talkshow every afternoon.
There's also no "either or" when it comes to offer-only casting. An offer cannot be made to more than one actor at once, and only one actor can be in negotiations at a time. You offer it to Actor 1's agent; You wait for a response; That response might take minutes or weeks; If the actor is interested enough, then customary vibe-check meetings happen; then negotiations occur to iron out the little details. Sure, these actors might be on the wishlist for Herbie –– they're on a lot of wishlists –– but that doesn't mean there is ANY reality to the situation.
As discussed in the other thread, it would be shocking if they can secure an actor who means MORE than Audra as either Herbie or Louise (even though they would benefit from an actor who means more than her). This is being billed as AUDRA GYPSY and any star with enough name value shouldn't want to play second-fiddle to her, be billed less prominently than her, and play a supremely non-showy role.
Speaking of Sudeikis: Hannah Waddingham for Tessie please. And she can be the alternate Rose at matinees. (I realize she wouldn't take on this featured role at this high point of her career, but she'd be perfect)
I love Colbert...but he was incredibly stiff in the NY Phil Company concert presentation in a very small role. I can't imagine he'd be a very good Herbie.