Thank you all so much for your words of advice as I made the decision. A fellow Franciscan, Lisa of Franciscan Focus, suggested checking into a book called St. Francis and the Conversion of the Muslims. When I visited the website she recommended, I found a link to an interview with the author.
I printed out this interview and brought it to the meeting. I decided to head this member off at the pass. I handed her the printout and told her that I knew she'd be interested in reading this, and if she thought that this book would be beneficial to the fraternity, we'd order a copy for the fraternity library. The idea of guest speakers was not mentioned. She was happy to receive the interview and said she'd let me know if she thought we'd be interested in the book.
So there we are!