No they don't .......your buying power isn't updated until the next day.
When you open a position the buying power is updated immediately.
When you close a position the buying power is updated the next day.
IB eliminated the $10,000 minimum to open an account - I believe there is no minimum now.
And as far as the net worth, income, experience level, etc. is concerned those answers can be fudged - brokers do not confirm.