If you fly BA, only earn 25% on most FF plans. If you can fly IB or AY then you will earn 100% on QFF, so that might be the best bet. But discounted economy is poor for your objectives, even with 40 flights per year -- you will get less status than for 1 F roundtrip on most plans, at least using BA. And I really cannot see justifying HEL or MAD routing for getting to ZRH or STR.

As for the best J to US/ME, BA wins easily at the moment. LH might do considerably better next year as the premium upgrades are rolled out. BA serves circa 20 cities in the US non-stop from LHR/LGW, and a similar number in ME, so great coverage as well as a solid J product. Of course you earn BAEC status quite quickly flying J on BA (unlike flying discounted Y on BA). So your requirements are somewhat contradictory.