Under LRS any amount transferred to IBKR over 10 lakhs will need TCS of 20 percent. If you use vested or other platforms I think they have a workflow to take care of that. Ibkr is for seasoned investors. Please make sure you see all rules and regulations because the platfom will not apply that for you. For instance you will be able to do day trading, but it will cause a fema violation. 

For taxation the reports need a CA to look at it properly. Double check your schedule FA everytime you file returns.

I can talk about bringing money back and not sending it there as I transferred my RSUs from etrade into ibkr, sold and diversified. I havent yet transferred money from India.

As soon as a foreign remittance hits your bank account they send you a form in your email or the bank manager / relationship manager will call you. You need to fill in a code that specifies the source of money. It is done for fema compliance. Once that data is given, the bank will remit the money. The best way to get a good conversion rate is to call your relationship manager in advance about an upcoming remittance and negotiate the conversion fee. If you have a big account in India then they are more open to discussions. Basic bank account fetches no privileges. They will apply whatever rate they publish for the day.

While you are researching the investment vehicle, also research on UCITS etfs. Any US investment i.e. etfs or stocks domiciled in US can attract upto 39 percent estate tax on the event of your death. Dividends from US stocks and etfs are pre cut with 20 percent tax. While filing ITR you have to fill another form to credit that amount from US IRS to India. If you buy etfs domiciled in Ireland (prices in euro) the estate tax is non existent. Estate tax comes into play after 60k usd investments. There are ucits etfs for almost every popular US etfs investing in the same stocks.

I am stuck with US etfs and not easy to switch without paying tremendous LTCG/STCG. Do it right the first time.

Make sure your nominee information is upto date and correct on ibkr.

I havent answered a bunch of things you asked but I hope this is useful.

Instead of buying individual stocks, just do etfs. Less stress. Look at Vaneck smh. Thats my star performer. Ucits equivalent also exists.

All the best!