1 When you work from Home, you need to consider whether the income accrues or arises in India. The nature of your services and mode of delivery of services will determine whether such income is Indian income. Generally such income is income arising in India and you need to pay taxes on such income, whether you are a resident or a non resident.
If the income can be treated as income earned outside India, then you will be liable to tax on such income only if you are a resident. If you are a Non Resident or Resident but not ordinarily resident, you will not be taxed on such income.
You will of course get the benefit of double taxation relief.
If the contract can be structured in such a way that the income earned from such contract is income earned outside India, then you will not be liable to tax in Indian on such global income as long as you are a Non Resident or a Resident but not ordinarily resident.
2 The taxes shall be calculated as per tax slabs applicable to you.
3 You become a resident if you stay in India for 182 days or more in a financial year. However, your status will then become Resident but not ordinarily resident if you have not stayed in India for earlier years.
4 If your turnover is Rs 20 Lakhs or more, you need GST registration. You may also need a GST Registration if such services are export income, even if the amount is less than Rs 20 lakhs but I am not sure about it.
5 Current account or savings account does not matter.
6 Depending upon nature of your services, quantum of fee and likelihood of continuity of such services in foreseeable future, you may do it either in your individual name or have a corporate structure.
Please take a professional help while structuring your contract that addresses commercial and regulatory issues.