As far as protecting the servos against a ground strike, your best bet is a small wire loop that keeps the servo from hitting the ground. With impact damage, a metal-geared servo won't necessarily break the metal gears. The force will move down to the nylon gears, and you'll still get gear damage. Protect the gears against impact in the first place.

If you're getting glitching due to long servo leands than you may have to use one of the devices you mentioned to alleviate it.

As far as chokes and such are concerned, Futaba does not make any.

A "choke" is a small coil of wire used to cut down certain types of resonance in its circuit. A buffer is a special type of amplifier between two coonneced devices. The buffer keeps one from influencing the other in an adverse way. A "booster" is an amplifier that increases the strength of the control signal so that the voltage drop of a large line doens't cause the signal to become too weak.