Yes the 7 channel rx should have enough channls for your application... You will use channel 7 for your gyro gain and channel 5 for your retracts...lights can use a Y connector if you plan on installing them....
I would suggest that you set up and fly your mechanics this way, as a pod and boom, first so that all trimming and checking is done prior to installing them in the fuselage... Makes for a much easier test flight later! !!
Good luck with your build!!!
AMA 2918-Team JR, Spin Blades, East Coast Scale Helicopter,Castle Creations