How can I check the non-business buyers’ orders in the business report?

You can check non-business buyers but not from the business report because the business report will show you the overall order details for all the buyers.
If you want to check non-business orders you can check them from manage orders.

Simply go to the business report, and select the timeframe for which you want to find out the orders, underneath the sales breakdown you’ll get the options to select non-business buyer or business buyer, the default will be the marketplace total, simply select the non-business buyer, and apply you’ll get the order details.