You only need a 4 channel radio for that setup. Yharnes on the ailerons and 2 pushrods on the servo for the rudder/nosewheel.

Your Futaba servos will work with any receiver - the most you may need to do is switch a couple of the wires at the plug (easily done with the tip of a #11 blade ).

The Futaba 6EXA is a decent radio. You may want to look at other brands also. JR is an excellent brand and for future growth, especially with no channel hassles, check out the Polk's Tracker III (about $200 with 1 servo ) and the Spectrum DX7 (about $350 ). Both have multiple model memories - the DX7 has 20 and the Tracker has 99.