Xiuying and Ren
Also the Tomato Convenience girl. If Ryo has asked her to help him out in the Yellow Head Building the local hospitals and morgues would end up flooded with beaten up gangsters
If he went one step further and just brought all of his friends with him (Izumi, Xiuying, Ren, Jianmin, Giuxiang, Hanhui, Eileen etc.) the YHB would be a piece of cake. The chase scenes would actually involve Ryo and his gang running after Dou Niu and the Yellow Heads, rather than the other way around. There would be nobody left on the 40th floor to fight. In fact, they'd probably have just agreed to bring Zhu Yuanda down by the time they'd smashed their way up to the 8th or 9th floor. 'Here, have him- he's not worth the trouble'
Also how about that tasty girl that works in the Thousand White warehouse? The one that wears leathers like another hot girl from Shenmue- the Jeet June Do girl. Add those two to my list