You really don't need dinner clothing in your carry ons. In 10 cruises, we have always had our luggage by 5 pm (although they won't promise that). If you haven't received your luggage, don't worry about dinner clothing--walk into the restaurant with your head high and tell the head server that your luggage hasn't arrived yet. They will fall all over themselves with apologizing to you! It isn't worth the effort of lugging dinner clothes around all day.
If you have late dinner, your clothing will definitely be there in time.
As to rotation, it is on your KTTW card. You can request if you have a preference. You can go to "dining changes" after you board if you didn't get what you wanted. And, in the long run...it really doesn't matter. It is "fun" to be in Lumiere's on formal night and Parrot on tropical night, but it really doesn't matter.