Last I heard the LY B744F deal feel thru. Up until about 2 or 3 weeks ago LY was talking to GECAS about taking 2 GE powered aircraft for delivery Sep 01, and Summer 02. From my understanding the price was a big issue with LY asking for nearly a 40% discount of GECAS proposed lease rates.
While yes these were to be GE powered aircraft versus LY's own PW powered B744's the deal included both a large spares inventory plus engine overhaul clause.
Having a split B744 fleet in engine types is really not that big a deal, several carriers including Air New Zealand, Qantas, Malaysian, SAA all operate more than one engine type on their fleets.
From the desert to the sea, to all of Southern California