#2 No, the MPL is not airline specific. A holder of a MPL can get a job at another airline on another type just as well as any other holder of a cpl/meir. Well...thats the purpose.
#4 No, it is not the intention of the MPL, the intention is to make a pilot education aimed at the right hand seat of a multi pilot a/c. Focus being on CRM.
The difference between a cpl and the mpl, is that in the mpl, it says " MEIR Multi Pilot Only"