1 - It is not Zakat. Zakat is - generally - purifying yourself by obeying Allah, by many means, including prayers, charity. .etc...By giving charity you are doing Zakat of your income.
The very poor people do not have to donate to charity. But the real believer can consider it regardless of his income. Regardless of his needs he can manage to do some charity as he could. If he does not have any, he can imagine that he has something to give. This is the real meaning of Zakat. It is dealing with Allah directly. Allah knows our real situation and capacity. We cannot deceive Allah.
2 - This is up to them together to decide. It is their mutual consent.
3- It is the same Salat, except we read the verse 18 from sura 3 instead of (Al Taheyyat ) and no shortening of Salat while traveling. The details are in my book about Salat in our site. About dressing, the woman can pray in any modest clothes as long she covers her legs. It is not required to cover her hair.
4- If somebody misses a prayer like the Fajr prayer, he has to pray it again, any time.
5- Wearing a golden ring or chain is permissible.
6 - Alcohol consumption is not permissible.