A1. by @Veremund :
Sorry, but yes it will. Wear a navy suit, change your grey tie for a black satin tie for dinner. Though if it were me, I'd change into a dinner suit for dinner.
A2. by @Testudo_Aubreii :
A tuxedo is appropriate to wear in the daytime so long as the main event at which it is to be worn begins at or after 6pm.
A3. by @archibaldleach :
I say wear a suit. It'd be one thing if you had a 4:30 ceremony and 6:30 reception, where you can argue that the overwhelming majority of the time you'd be in the tuxedo is after 6:00. In this case, your ceremony and reception both start before 6:00. Traditionally, if one were to break rules regarding whether to way daytime or evening formal attire, one could wear daytime attire into the evening but would not wear evening attire in the daytime. Since there's no taboo or issue associated with wearing a suit and tie no matter what time the ceremony and reception are, that's your safer (and smarter) bet.
Have a question about your wedding? Ask it here.