Yes, you're right in customizing the sales receipt template in QuickBooks Online (QBO), @SBH2.
Being able to remove the Bill To and the Balance Due field is currently unavailable. It is a built-in feature of the QuickBooks sales forms to determine the balance of the transactions and the bill to details.
When importing a customize template, these fields might also be added when mapping.
For the time being, you may look for a third-party application that will fit your organization's needs with sales receipts, then integrate it with QuickBooks. Here's the link: http://apps.intuit.com/.
For more tips about managing sales receipts in QuickBooks, you can open these articles:
I also recommend checking out this link for more information about how nonprofit organizations use QBO.
If you have any other questions, please feel free to leave a comment below. I'll get back here as soon as I can to help you again. Have a great day!