As far as I know, audio doesn’t need to go in matinee. just place an ambient sound object in your scene and assign an audio file to play from that.
Have you considered rendering everything and editing the video in a non-linear editor program? (Final Cut Pro, Adobe Premiere, Avid, etc)
This would give you more flexibility. If you’re concerned about lower-grade laptops, you could edit the video in a separate program, cut things how you want, render it to a video file, then send that video file to whoever is showcasing to the audience.