Is there a way for me to BCC the customer's assigned sales rep on the order received email from a SuiteCommerce site? There is this BCC field, but it is not dynamic and requires specifying exact email addresses, which will lead to lots of people getting emails they don't need. Is there an alternative way to get the exact order received email BCC'ed to the customers sales rep?

Sounds like you would need to turn off that email and sent it using your custom logic: workflow/script + email template (custom).