As long as the servo leads are as far as possible from the ignition system, you should not have a problem with ignition noise.
The electric retracts can be plugged into a standard channel output on the receiver.
S-bus servos are "daisy chained" through the S-Bus, but you can connects a variety of servos to the same chain. As long as you have sufficient power, you should be OK.
Thanks Bill! that's awesome. I had assumed that if I was running SBUS servos I couldn't run standard servos off the receiver. how about the sbus daisy chain? can I wire up a multi servo lead that will include a switched power source from each wing nacelle? (imagine a 4 way Y-cable)