I understand from the previous posts and other things I read on this forum that in order to use a BA one partner award, all segments must be on flights operated by the same airline.

I'm interested in travelling from the Washington DC area (BWI, IAD, DCA) to Singapore with a several day long stopover in Tokyo; therefore, I wanted to use BA miles for the redemption because it allows the free stopover. I found the following flight options but believe that neither will work for a one partner award because of codeshares.

1. JAL (ITA software search shows this as a Japan Airlines flight):

Segment 1 - BWI to ORD - Japan Airlines Flight JL5589 (operated by American Eagle for American Airlines, also American Airlines Flight AA4260)

Segment 2: ORD to NRT - Japan Airlines Flight JL9

Segment 3: NRT to SIN - Japan Airlines Flight JL711

2. AA:

Segment 1 - BWI to ORD - American Airlines Flight AA4260 (operated by American Eagle)

Segment 2: ORD to NRT - American Airlines Flight AA153

Segment 3: NRT to SIN - American Airlines Flight AA5836 (operated by Japan Airlines as Flight JL711)

My questions are:

1. Are American and American Eagle considered a single airline (for BA one partner awards)?

2. Am I correct in assuming that the best option if I want to do this trip is to buy a separate flight from WAS to ORD, and use the one partner award on JAL?

Thanks in advance for any advice.