German Tax System (Hamburg)

Hi everyone,
my name is Nicola and I'm going to move to Germany. I have some questions about the tax system.

1 - If I work and live in Germany, and my wife works for an Italian company (earning less than me), is it possible for me to access the tax class 3, with the consequent benefit in terms of taxes?
2 - I suppose that my wife will pay taxes in Italy, also once she will become a German resident (according to the bilateral agreement between Italy and Germany). Indeed there is the possibility that my wife will continue to work for the Italian company also when living in Germany (as an employee). In that case, do I have to declare the income of my wife to the German Authority? How does it affect the tax class and the total amount of taxes to be paid?
3 - The next year, in the first months (I guess up to June), the two children of mine will remain in Italy. In this case, can I declare them as dependants also if they continue to live in Italy?

Thank you very much for your help.

Best Regards

Nicola