Mikey,
I'm a firm believer in spend the most you can afford on receiver and servos. That being said, I like the idea of updating to the AR9100 (I use them for my stuff and they are great) if only to get more remotes on the plane. You can still use the AR7000 but make sure that you use the logger to do a very thorough ground check (in all directions, have a friend turn the plane for you as well as hold it's tail up and spin it) if the flight logger says you are good, go fly, if not keep moving things until you are good. With only one remote, this becomes more critical.
Depending on the type of flying, you may not be completely happy with the servos but they will work just fine, it really is a matter of personal preference. I have planes with 5645s and they are slower than anything else I have and the centering could be better (using a hitec programmer you can adjust the dead band to get a slightly better response). The 5735mg is a big servo (in size) but may not be enough for some 3d antics on a 33% plane, you have to try it and see how it flys for your style of flying. If you sport fly and do some (basic and sportsman) IMAC these will probably work just fine, lots of crazy aerobatics for long periods or higher precision IMAC means that you may be happier with some of the better options out there.
Some people also like a fast servo on the throttle as well (especially for 3D).
Remember, these are just opinions, take all of them with a grain of salt (even from me
) in the end you need to match your required performance with the way you like to fly and what is in your budget so you can fly.
Good Luck and Have Fun (we're supposed to be having fun, right?)!
MadDog Joe
Flying MadDog Aviation