Thanks to everyone who offered ideas! We had five families participate in all or some of the seminars which was a nice size group for discussion (5-10 people). It also opened discussion with a few people who didn't participate but nonetheless wanted to know how it was going or what it was about.
For anyone interested in doing something similar, here is a record of what we covered: http://perspectivesoncreation.blogspot.com
There were varying opinions of the Origins book, but I think overall it was the gentlest way to introduce the concept of real Christians holding old earth and/or evolutionary creationist views. A few people would have preferred a book that presented all 4 views (YEC, OEC, EC, ID) with no preference/bias...but I hadn't seen anything like that from the post-human genome project era Maybe the new book in Zondervan's Counterpoints series will fill that void https://www.amazon.com/Creation-Evolution-Intelligent-Design-Counterpoints-ebook/dp/B06XFN3TW6/.