None of which addresses the fact that Michael has a tremendous amount of foresight (higher Ni), excellent management and organization skills (Te), and seems unconcerned with intricacies, deduction and little nuggets of reasoning (no Ti). Any type can easily behave like another type (I act nothing like a typical ENFP, but I'm Ne Fi Te Si), and just citing type descriptions is a lazy and pedestrian way to argue type theory.
The last paragraph doesn't describe Michael at all, in any case. Out of him, Fiona and Sam, he's the one who always takes a step back and plans what comes next. He's a man of action yes, but he never goes in unprepared. Fiona (ISTP) on the other hand, always wants to immediately dive into the fray.