When Steve tracks down Mary in the park, you can see their breath, even though it is supposed to be June. However, at night in San Francisco, it can get that cold.
In the park, there's a tight shot of Dr. Edison flicking all the "non-brown" M&Ms out of his hand but when he explains why he's doing it his hand continues to move. Then when it cuts back to a medium shot, colored M&Ms are back in his hand.
If Mary is a professional wedding planner who read the Donnelly engagement announcement and was going after the account, there is no way that she would not have known the full name of the groom, not to mention the fact that he is a doctor, regardless of the nickname Fran used for her fiancé.