You have an airwire on the PCB?
C2 is very close to the edge of the PCB. There is plenty of room for improvement of the PCB layout, but it is not critical. Make sure your design rules are set for itead and dont push your luck by using the lower end of their specififcations if you can.
Regarding schematic and component values, if you have read and followed the datasheets of both parts you will be fine.
About the BGA footprint, you can mirror the top layer and print it on an acetate transparency. Then flip the memory chip over and overlay the acetate print to check your footprint. Of course you can rely on the datasheet package dimensions if you are confident.
Happy hacking.