Hey Bill 🙂
Thanks for reaching out! We’d be more than happy to have you using Events Calendar PRO for your Non-Profit site!
With that said, your best route would be to submit a request through our contact form. We check the email daily and typically respond within 24 hours.
Also I would like to utilize it in the development stage before cut over to the final URL.
You are able to change the url your license is being used on at any time, whether it be a staging environment or your live site.
I hope this information helps and thanks again for contacting us. Best of luck with the site and NPO approval – have a good weekend!