Could someone please advise:

1) Can GUF2 be applied if one of the two legs is operated by AA (on a BA flight no)?

2) Can GUF2 be applied to a multi-city itinerary (LHR-LAX, SFO-LHR)?

3) Which travel agents other than Propeller are familiar with GUF2? I haven't had much luck with AMEX.

Many thanks in advance