I think E-BRC is just there if you wish to claim any benefit of export scheme other than that its not required.
I am not too aware about your second question but I dont think CSB 5 data reflect in EDPMS system.
The payment gateway like transferwise only issue FIRC for receiving payment for you from outside India and not while depositing amount from transferwise to your bank as it would be inward remittance for them when they receive payment.
I don't think inward remittance cost is such high as we are handling tax for some service exporter and their remittance cost is not much.
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