I don't really understand the legal situation in your country and may not provide any solution in your opinion. But I have a suggestion for you to consider.
Maybe you need to create a bank account specifically for your new business. This will make it easier in your business income reporting even though you have another bitcoin business.
3. From your experience, will this trigger an audit to any greater degree?
Not so sure, then the things you must provide and consider are...
legally required
Yes, most will concern the privacy of your customers. So your trust is at stake here.