I could come along with some translation of the names. I don't know, how Isshin is written in Kanji, the Japanese characters, so I'm not sure. It could be "one mind or heart", "one person or onesself" or "to renew something". It would all make sense as a name of an MA style. I didn't find anything for Fu, but it could come from furu, which means old. Ryu means flow, style, school.