Can family apply in Switzerland together if only father is resident in Switzerland?

Hello, I am German working in Zurich on a C-permit. For school reasons I temporarily moved my family to Mallorca, Spain last year and they returned their C-passes. They are registered in Mallorca but not as residents. My children have German and US passports, my wife a US passport.

1. Can we apply for the Visa to China in Zurich as a family? 2. Can they all apply in Madrid? 3. Do my kids have to apply in Germany and my wife in the USA?

Many thanks for you help!