Those choices should be fine. From what I hear, you will have a wide range of attire from people wearing the bare minimum of what the dress code allows to much nicer clothes. For us we will wear Pirate costumes on pirate night, Nice dresses for girls and suits for guys on optional formal night, and Summer dress for girls and khaki shorts and dress shirt for guys on the remaining two nights. The optional formal is just that, optional, so there will be those dressed up and those not. We are big picture takers so every night we will match because if my wife doesn't do anything else on a cruise, she WILL be taking a family picture!
Try to pick a time that you plan on arriving, but if you are early, unless the terminal is full, they should let you get checked in, your boarding number may just be a little higher.