Maybe not that likely but i think we need to take into account the option of Haneda being a member of B.O. Profile wise i think it fits quite well. Being a renowned shogi players make him be able to meet some big shots shogi fans. They can meet in private without that much suspicions. Amanda was a wealthy woman, having connections with FBI/CIA so maybe they requested her to play the role of a customer to get proof that Haneda is a member of B.O or data on B.O.
Concerning their murders scenes. We know that it probably has 2 culprits. Amanda's death was quite clean whereas Haneda's death is a 'messy' one. By this point, we can guess that Amanda was probably killed by B.O whereas Haneda was killed by someone else. But then why Haneda's dying message contain some key words related to B.O? How come Haneda was on the List of APTX victims? What role play Asaka (Amanda's Bodyguard) at that time?
So far in the story we can suppose that Wakasa Rumi is probably Asaca. She has the strengh to play the role of bodyguard, her age fits well, she has the APTX victims data and her name contains 'Akasa'. Also we know that the website of Haneda's incident is regularly updated and if we take into account the fact that on how the full data of New Teacher's Skeleton case was leaked on the web and that the only one able to do that is probably Wakasa.. we can conclude that Akasa and Wakasa is probably the same person.
If Akasa was really a bodyguard and not a member of B.O. It will be impossible that Amanda will be killed so easily. My idea is she was killed by APTX by Haneda, however the effect of the drug was different at that time : it has a time delay effect. That explains why Amanda was killed without Akasa being able to do anything and why Haneda's room was filled with Amanda's fingerprints. The crime was perfect, she doesn't have any proof that Haneda killed Amanda. However this is possible that Amanda shared some informations with Akasa on how Haneda could be a member of B.O, thus Akasa may have decided to kill Haneda to avenge Amanda (not impossible if their relation are close). Then she ransacked the room in search of some data on B.O, she probably get on hold of a way to access to their site that's why she have the APTX victims data.
Concerning the key words we know it may refer to both 'ASACA RUM' or 'CARASUMA'. I think this is possible that Haneda left the dying message 'ASACA' during the time delay effect of APTX but then Asaka added 'RUM' to change it to 'CARASUMA'.
PS: I know my theory is quite crazy, wanted just to add another option. Haha.