I like the reference to Hope, and with both yours and Smallknight's characters as what Pona would call "street toughs", I have a feeling I know how we can bring everyone together. We'll add to it when more people sign up, but basically, I'm thinking that Pona still works on the side as a healer in the slums, so she also knows Hope, and by extension she knows Mao. Kaytora, as another "good guy" living on the streets, could know of the orphanage and Mao, and could be helping him protect the orphanage, something like that.
Pona goes out to the Lower South Side to recruit Mao and Kaytora as muscle, and to help her track down the killer(s), but they won't help until the orphanage is safe, so the first act involves dealing with the new gang on the streets and protecting Hope and the orphans. Thus, everyone (so far) is together, and Dragonbeard's main story can emerge as we deal with the gangsters. Does that sound good?