sharksucker
The first visa that you need is from the school that you going to for the FAA CPL.
When you move to Alpine Air you will need to transfer your visa to their school. The first school will start the transfer by transferring you out in the Sevis system, then the new school will transfer you in. The process takes about 2 business days to complete.
The background check can take up to 45 days and therefore I recommend that you complete this asap.
Have fun!