cool idea and servos are cool but the gear might be an issue - why not a low voltage geared motor with a off centre wheel that could lift and drop the stay puft.
here is a video of a test rig I did for a small project - geared motor with a wheel with 2 triggers arms on it. Instead of the wheel with the 2 trigger arms have just a round wheel but hubbed off centre so gives you an elliptical movement and then when placed right can lift and raise stay puft. Or alternatively a egg shapped disc with the hub recess in the centre to give you 2 different motions or swagger.