I'd very unlikely be flying BA, but they require 4 qualifying flights per year for Silver. Would you recommend that BAEC is most appropriate FFP in this case even though I'd fly to South East Asia?
So consider QR or IB ffp.
The airline you fly and ffp you credit those flights to does not need to be the same airline.
Any ff miles/points/avios from credit card spend (branded cc or transfers),
Check expiry is you have avios in BAEC