“Dirty Love” and “Townie” author Andre Dubus III was the honoree at the Newburyport Literary Festival over the weekend. Other authors who made appearances at the event included Jenna Blum, Claire Messud, J. Courtney Sullivan, and Wally Lamb. . . . Best-selling novelist Walter Mosley and Jane Friedman, editor of the digital magazine Scratch, will deliver keynote speeches at Grub Street’s Muse and the Marketplace next weekend. The literary conference runs from Friday to Sunday at the Park Plaza Hotel.