Is using a font to promote a Make-A-Wish Silent Auction considered commercial use?

Fonts generally are not copyrightable and are available for any use.

You should consult with a lawyer. Usually, fonts are not covered under copyright, but you may have a contract for the particular service you are using. Show a lawyer who knows about intellectual property where you are getting the font from, what the terms of service are, and what you are doing with it. The lawyer will be able to help.