While I'm trying to clear the pending queries to be answered by me, I'm amused to see your queries and the responses thereon. As you seem to be frustrated with the replies, I venture to address your queries, which normally I would have avoided, if they are specifically addressed to other experts. This is just to assure you that we care for your concerns.
Now let me just clear some confusion you have regarding GST and Income Tax, as you are from Netherlands and have no knowledge of this subject. Income Tax is a Direct tax, levied on the incomes earned by you exceeding Rs 2.5 Lakhs p.a. GST, on the other hand, is a new Indirect tax that has come into existence from 1st July 2017 by replacing other indirect taxes like Excise Duty, Service Tax, VAT and others. You need to be a registered supplier of goods or services, if your turnover exceeds Rs 20 Lakhs p.a. I hope now you have got basic understanding of the Income Tax and GST. Please note the difference between Income under Income Tax and the turnover under GST. Income is the net profit after meeting all your business expenses out of the gross receipts from your profession.
Now let me address your specific issues:
1) Your present turnover is now Rs 20-30K p.m., which is less than Rs 10 L p.a. Hence there is no liability towards service tax, which is now defunct, with the introduction of GST.
2) Your proposed turnover is expected to be Rs 50K p.m., which is also less than Rs. 20 L p.a. Hence, you need not get registered under GST also mandatorily but you can still get registered voluntarily. However, if you are a casual supplier, you need to get registered even if your turnover is less than Rs. 20 L. A casual supplier means you visit a place and provide services there, which is not your usual place of business.
3) Another important issue is the place of supply for the purpose of GST. If you are providing services from India, you will have liability towards GST but if your place of supply is outside India, you do not come under the purview of GST.
4) A similar issue is the place of accrual of your income. If you are providing your services in India, you need to pay Income tax on such income. However, if you are providing services from outside India, you need to pay taxes only if you are resident in India, i.e., if you stayed in India for more than 182 days in the financial year.
5) A financial year means the year commencing from 1st April to 31st March of the succeeding year. Thus the financial year 2016-17 means the period from 1st April 2016 to 31st March 2017. You need to file the Income Tax return by 31st July 2017, if your income exceeds Rs 2.5 Lakhs. The assessment year follows the financial year. Thus for the financial year 2016-17, the assessment year is 2017-18.
6) You need to link PAN card with Aadhar Number. This can be done very easily by visiting the Income Tax Department portal at www.incometaxindiaefiling.gov.in
7) From your queries, it appears that your place of providing services is India only but I'm not sure how you are carrying on such services from Netherlands. If you are carrying on your services from Netherlands to your customers in USA and UK, you need not worry about Indian taxation.
I trust I cleared most of your confusion.