You're in a tough spot trying to go for double elite with only 40K BIS travel annually. Elite Plus gets you lounge access on Int'l itineraries, which sounds like it is the main benefit you'd achieve. You would also get more RDMs because of the higher bonus percentage there. I don't about 8 years for Mornig Calm Premium, but I would generally say that you should pick one FF program in the alliance and stick with it. Otherwise you're probably diluting your potential benefits.
S.