Mortimer and the Riddles of the Medallion, released in 1996, was published by LucasArts (EDIT: apparently during the time period after the learning division(s) merged into LucasArts, but before Lucas Learning was spun back out into its own division).
According to the Los Angeles Times, The Mystery of the Disappearing Ducks: A Paul Parkranger Mystery (released in 1991 or 1992, and was the winner of a Cindy Award for special achievement in instructional design) was only one of at least two of these types of instructional discs released by Lucas in the early 1990s. The other was GTV: A Geographic Perspective on American History (released in 1990 or 1991, and was selected by Technology & Learning magazine as one of the top five educational software programs for 1990-91).
EDIT: I did a little more digging. SFGate revealed a third early 1990s educational disc by Lucas: Life Story: The Race for the Double Helix.
EDIT 2: More digging. According to the New York Times, the learning division of the Lucas companies was founded in 1987 as LucasArts Learning. GTV was made in association with the National Geographic Society, the California State Department of Education, and Apple Computers. Life Story was made in association with Apple's Multimedia Lab, the Smithsonian Institution, and Adrian Malone Productions. Paul Parkranger was developed in association with the National Audubon Society (which we already knew).
LucasArts Learning also developed an experimental program titled Mac Magic, which was developed in association with the Marin Community Foundation, the San Rafael, Calif., School District and Apple Computers. It was a cooperative learning program for classrooms that taught language and history skills to ethnically and academically diverse students. It started in 1989 and ran for at least four years. It was awarded the "Point of Light" award from President H.W. Bush in January 1993, less than two weeks before he left the White House.
EDIT 3: According to a New York Times article, LucasArts Learning was merged into the LucasArts Entertainment Company in 1993. And according to the Los Angeles Times article above, the learning division was then spun out from LucasArts as Lucas Learning in 1996.
EDIT 4: After even more digging, T.H.E. (Technological Horizons In Education) Journal revealed one more videodisc for classrooms by LucasArts Learning: Choices & Decisions: Taking Charge of Your Life. It was developed in association with Visa. It was used in at least six classrooms beginning in 1992 and taught students financial management and consumer life skills.
EDIT 5: Apparently, according to a New York Times article, George Lucas created another learning division in 1989 after filming Indiana Jones and the Last Crusade titled Lucasfilm Learning Systems. GTV was published in 1990 by that division.
EDIT 6 (8 hours later): I decided to do another search, and the 1992 book Transforming American Education mentions another Laserdisc title by Lucasfilm Learning Systems in the GTV series: GTV: Planetary Manager. It's an exploration of the connections between science, the environment, and society.