RE: Is a 6 channel reciever enough?
The Tiger is a great airplane - be prepared to fall in love!
As for the servo, Jr plugs will fit into a Futaba Receiver, but Futaba won't fit into a JR Receiver because Futaba adds a small tab to one side of the plug.
The good news is - IF your servo comes with Futaba plugs, you can grind/file/sand the tab off and it will fit a JR