So, is your plan to leave Paris in the morning (the earliest train I see is at 6:01 arriving 8:42), drop your bags at the hotel, have a guided tour of Normandy (would have to be a private tour, not starting before 9:30), leave Normandy by 4:00 and have private driver take you to Mont St Michel (90 minutes), spend the evening on the island, leave by 10:00 am back to Bayeux (again a private driver?), spend the night in Bayeux, then train back to Paris (nearly 3 hours) to catch the Eurostar?
Have you traveled like this before? The reason I ask is that this will be exhausting. There are enough hours in the day to do this, but if you are too tired, you won't enjoy it. If I were you, I would definitely drop something.
Good luck on your planning! Please let us know what you decide to do and how it turns out.