As for A321neo production slots, ATDB says the following:
- MSN 7428: A321-271N, Qatar Airways
- MSN 7486: A321-271N, SriLankan Airlines
- MSN 7501: A321-271N, Qatar Airways
- MSN 7530: A321-271N, China Southern Airlines
- MSN 7535: A321-271N, SriLankan Airlines
So if QR is out, SriLankan or China Southern may become the P&W launch operator while Virgin America is set to become the CFM launch operator.
Since time eternal the "launch customer" has been defined as the customer(s) that puts up the $$$$ to launch the airplane, only recently have some people construed it to mean the first customer to fly the airplane. ILFC is the launch customer for the A321NEO regardless of who takes delivery of the first airplane.
There were 4 launch customers on the 777X (Lufthansa/Etihad/Qatar/Emirates) but only 1 will take the first delivery.
A "launch operator" is somebody who drives a boat.