Dear Mr. Johnson,
Thank you for posting your request on the History Hub!
Various offices within the Department of Defense have informed us that no agency of the Federal Government has ever compiled comprehensive lists of all individuals who served in the U.S. Armed Forces in all the wars/conflicts from particular states or communities. If you have not already done so, we suggest you contact the Illinois Adjutant General's Office or the Illinois State Archives’ Databases of Illinois Veterans.
We hope this information is helpful. Best of luck with your research!
This is after your planned talk, but just in case it's useful for the future- the National Archives' Access to Archival Databases site has searchable databases for military casualties for various conflicts. There are Korean and Vietnam War casualty databases that are searchable by the hometown of the soldier.
I searched for Centralia, IL and found the following results-
Korean War Extract Data File- Results page
Vietnam Conflict Extract Data File- Results page
Obviously this isn't a comprehensive list of fallen military veterans, but it might be helpful as a starting point!