Well, I need RP for both, but I am definitely in a better place(plotwise) with Sawenah... I mentioned Niamh because I thought you were in Matori XP . We can save the plot with him for a rainy day when you find yourself in/around Matori.
At this point, Sawenah is in Oba and has just met her father, got her merchant cart fixed, and unknowingly joined a guild of merchants to get out of trouble with the law... Maybe she could just get overwhelmed by all the new stuff in her life and storms off to wherever you need me to be for these two to bump into each other. Masika can be the sweet thing she seems to be and inquire about what's got Sawenah all in a huff and she can just start ranting about how her life is changing. And likely once she realizes who she is talking to (essentially, just the fact that Masika's part water earthling and Sawenah later learned of what the Obans were doing to them in the war and that she (unknowingly)fought to preserve that) and just feel horrible and shut down XD. Then Masika can just try to coax her out of her funk and get her passed her apprehension toward the Matorans?
(Just trying to get a rough outline as to how this is going down before we jump head first into an RP. Feel free to add/alter/erase as needed XP)