jetBlue and United could not 'merge' with EI in the traditional sense. They could own up to 49% of the airline, but no more, same with Ethiad or any non-EU carrier. B6 have already discounted interest in mergers, I believe. UA are going through integration of UA into CO at the moment, so can't see them being too interested either.
LH group - not sure how interested they would be in a heavily Leisure/VFR business on the periphery of Europe, their experinece with bmi would suggest they have little interest or appetite in this market. They canned almost all the charter flying, all the long-haul from MAN, the point-to-point form LHR and so-on. If it's a German airline you are after AirBerlin would be more likely, in their guise as Ethiad's European arm.