First off, you cannot connect the XBee to the Rx,Tx [pins 0,1] at the same time as using
the USB port, as they conflict. You can disable the USB port by running the board off an
external battery.
Secondly, the XBee is a 3.3V only device, so you need to check if the adaptor you have has
5V to 3.3V level-translators. Some do, some don't.
Thirdly, you should not be trying to run a servo off of the 5V output pin of an Arduino board,
as the servo current can overload the voltage regulator, especially on bds with tiny smt
v.regs. Best to use a separate battery for the servos.