Yeah, she is based on a daimyo called Matsunaga Hisahide.
His relationship to Nobunaga almost the same as Tsubame to Momoyo.Tsubame's weapon got its name from Hishahide favourite Tea kettle.
In fact lots of characters from S and A are based from Chinese's Water margin and Japanese historical such as Minamoto no monogatari and Sengoku jidai.