Cor Not quite sure what kind of information you're looking for, but there is a Pricing Sheet that includes all details about how bunq will bill you in relation to your account usage. And if you think the Support told you anything that would be interesting for the community and is maybe not yet publicized enough, by all means feel free to share it here with everyone.
If you're wondering about OP's question: Yes, you need a personal account to have a business account. But for the personal account you're free to choose whatever plan you like. So that can also be the Easy Travel plan if you want to avoid any monthly costs there.