I think the new book's going to focus on Mala's family. In case anyone is actually paying attention here, you may remember that in "Other Cities," we learned that Aravindan had a younger sister, Mala, born in 1928, whom he left behind in Sri Lanka when he went to Oxford. At Oxford he met Shanthi, and the two of them eventually moved to Hyde Park, where he was a professor at the U of C; they had six daughters, whose stories comprise about a third of BiM.
I don't think you ever learn anything else in BiM about Mala, which gives me a lot of freedom to play with her. I think she stays in Sri Lanka, marries at eighteen, has several children. And at least one of those children is going to end up in Oak Park. Okay, not actually Oak Park -- I think I'm calling it Riverwood. But a fictional Chicago suburb based heavily on Oak Park. :-)