1) In your 2nd paragraph you said 'back to TLV' - does that mean you started there? If so, and your journey is now back at point of origin, I think BOS is scratched and you'd have to buy a new ticket to the US to make that appointment.
2) Can try claiming cost of LAS hotel from AA, but LAX hotel from travel insurance.
3) Claim original routing with BA Executive Club, sending ticket numbers and boarding passes to support.