[jasonbvr]

There are Chinese schools much like the plethora of English schools in Japan, but they are a bit harder to find. Her best chance would be to a) have awesome Japanese ability and work in translating/tour guide of some sort, b) know Mandarin and work in one of these Chinese schools, c) find a school that teaches Cantonese which I would assume there is at least one or two in cities like Tokyo, Osaka, etc., or d) get a job with a Chinese firm that will place her in Japan.

I have never heard anything about having a child care certificate making it easier to find a job in Japan. Maybe it would if you were Japanese or in her case working within the Chinese community (second largest percentage of foreigners in Japan after Koreans).