Overall your selection will be fine. Hitec and JR mix well together. I don't personally care for Hitec, but a good many others do.

I believe that you will have a personal issue with the speed of your throttle servo after you get the plane up and flying. The high peformance servos used on the flight surfaces are faster and much more precise. What will happen is that after you get used to the plane and you start into a bunch of 3D stuff you will have problems with the timing between the throttle responses to the maneuvers. A digital or coreless servo would serve your needs much better. Even a "baby" digital like the standard JR shipped with their radios would be better for the throttle. Ask RTK. He's experiencing the same thing right now.

Most good digitals will make some noise when they are working. Unless you have balanced your control surfaces, and most do not, a digital servo is not truly at idle when at neutral. It's holding up the weight of the flight surface to maintain neutral. It shows up quickly with the better digitals when you turn the radio off. The horizontal flight surfaces all drop if you don't have a lot of bind in the hinging.

If your going to need to purchase batteries, why not spend a few dollars more and get lithions and fly for several days on a charge and come in lighter that with the nimh? No memory, hold a charge for months at a time, lighter weight.

Plugging 2-6v batteries into the Rx won't hurt anything. You should not need a regulator with a 6 volt installation. Don't do that with the ignition unless the manufacturer specifically states that it's ok. In that area stay with 4.8 volts. Some servos will be a bit "jumpy" on a fresh 6 volt charge, others will not. This was originally particular to the JR 8411 servos.

Pat