Good quiz but I might argue that Robespierre would be a better analogy to Cromwell. They were both radical revolutionists that introduced republican ideas to their countries but failed to retain the power. Napoleon, in contrast, was able to establish a dynasty.
Thatcher one doesn't work. Margaret Thatcher was "Prime Minister" (Head of Government) of the UK; Mary Robinson was "President" (Head of State) of the RoI.