I am more interested in the board routing from USB connector to the chip. Wan those traces nice & short & without lots of vias.
The more 0.1uF caps the merrier. Maybe not on the xbee, I would have one for the SD card tho.
JP4 allows the card to be powered from VUSB? I would include a PTC resettable fuse also between the USB connector and VUSB, keep someone from damaging their PC if something should happen when JP4 is connected.
1812 size
1206 size