Mail Merge - New Thoughts?

I implemented this same field at the start of the year. I added a formula field to my opportunities for name and address fields. Now I use a checkbox on the donation to send out a standard receipt to the primary contact email, with name, address, and other donation fields merged. It goes out immediately upon the primary contact being not empty and setting the checkbox, using a workflow rule. The rule sets another checkbox that indicates the receipt was sent. I'll redo all this later this year to use the newly provided field, the donation acknowledge fields and PB. But the primary contact field lets me send out one receipt per donation to the primary contact using standard and free tools. Big step forward since this is a frequent operation!

Doesn't solve sending to everyone in the household. Doesn't solve a cumulative household giving report. A receipt to everyone in the household is possible using flow and PB, but I haven't investigated the best watt to format the letter from flow. (Htmlsend would be my bet.) AFAIK, a cumulative detailed household giving report is still not possible in native SF without code, but I'd haven't tried with the new HHA model. It could be possible from the HHA using a Visualforce template since all donations are sitting on that one account! But there are a lot of details to iron out fit that to work.