Suggestions by @moosenoantlers

Matthew Goode

as Michael Hardcastle in The Seven Deaths of Evelyn Hardcastle

LaKeith Stanfield

as Charles Cunningham in The Seven Deaths of Evelyn Hardcastle

Sophie Turner

as Lucy Harper in The Seven Deaths of Evelyn Hardcastle

Judi Dench

as Millicent Derby in The 7½ Deaths of Evelyn Hardcastle

Idris Elba

as The Plague Doctor in The 7½ Deaths of Evelyn Hardcastle