I don't think Mao will travel to US for Yuka. I also love the idea of YUka being her coach. I think Yuka's father will be good as the main coach and a few tech/ spin coaches to include Lucindah for spins (she speaks Japanese)
What a great idea: Lucinda Ruh as a spin coach. She does indeed speak Japanese. In fact, I remember from a long-ago fluff piece on a televised pro competition (Landover, I think) that Yuka herself said that Lucinda's Japanese was fluent enough to have a conversation. Lucinda's father's business career took him to both Japan and the U.S. for several years at a time. I think Mao is gifted enough to benefit from spin training. Another wish-fulfillment idea...pigs might fly before it happens, but it's fun to imagine how it would go.