Welcome to DIS. I also call it planning ahead. DH was happy I did it once we were on board!
As far as requesting a rotation, when you check in, at the bottom of your Key To The World (KTTW) card, you will see your rotation in letters (something like LAPLAPL). It's not a hard and fast rule, but generally, people with little kids have APLA, mid-range kids have PLAP, and older teens or no kids have LAPL. I've never worried too awfully much about being in a particular restaurant for a particular theme. For my family, we typically fall into the PLA rotation, and Parrot Cay is my least favorite restaurant (it's too noisy for me). Our last cruise, we were on the Wonder, and got the TAPT (Triton's instead of Lumiere's on the Wonder) rotation. If we get PLAP on our next cruise, I'll request a change to LAPL.
There is a note about requesting dining changes on your welcome aboard navigator. Most people are trying to request switching from late to early seating, but they can change your rotation too.