Regarding #1: Yes... to have adequate clearance for the PARKING brake, you will need to either install thinner connectors or notch the taller ones for the cable to pass through. Check the picture below.
#2 The front and rear rails are NOT parallel. If you want the connectors to run in a straight line front the rear rails to the front, you WILL need to tack them at the rear and then pull the front end into position and weld.