First off, let's get clear on what your "IB broker company" actually does. Are you just gonna be sending clients to a main︀ forex broker and collecting a fee for it? Or are you planning on actually handling︁ their money, like taking deposits or making withdrawals for them, or even trading on their︂ behalf?
If you're just introducing folks and the main broker handles all the money and︃ trading, then your banking needs are gonna be way simpler.
But if you're gonna touch︄ client money at all, even for a hot second, you're gonna need a serious financial︅ license (think big-time regulatory stuff) and a special bank account just for client funds. That's︆ a whole different ballgame, way more complicated and regulated.