I can see Harry's mom as an early plotter into the BC. A BC that might have been more altruistic in the beginning and was quickly corrupted by more sinister members. That could suggest that a controlled use of outsiders was a possible plan of action.

I also believe she was a part of the blackcouncil/The circle briefly. I assume it was as a new recruit through Lord Raith (I take his magical protection as outsider power at work and him as a top tier minion, possible member) as she was his consort and she then learned of some sinister goal and wanted out and was killed for it.

I don't buy that she while under influence of Lord Raith managed to spy or divine something of him. BC is practically impenetrable and he is a White Court vampire which prides itself upon deception and stealth for even more secrecy.