As for the the tail vibration. A lot of that is normal. What isn't normal is looseness in the control surfaces. make sure that the rudder and elevator surfaces don't have any slop in the movement, because that will translate into flutter in the air. But the entire tail vibrating is normal.

As for your receiver and batteries. Wrap them in foam rubber and put a rubber band around them to hold the rubber on. Then I set small eye hooks into wood blocks epoxied into the fuselage where you want to mount the receiver and battery. Then use rubber bands hooked to the eye hooks to hold in your receiver and battery. This set up will cushion the components from normal vibration, and will protect them in the event of a crash.

Hope this helps.