Possible. But would you do a last minute recast of the role for a name actress if she doesn't have that many lines? OTOH, we've seen very little of the Hellfire Club scenes in any of these trailers: again, either it's not a very big part or it's being hidden intentionally. 'Scary upper class 60s monster' is Jones's wheelhouse right now.

January Jones wasn't my first choice for this role, and I'm nervous about it - especially given the rather random appearance of Emma Frost in the OTHER X-Men film we don't consider canon.