I am looking to contact someone with expertise in the area of disability benefits offered by the Defense Department and the Department of Veterans Affairs, and knowledgable about the differences between the two systems, and about Combat Related Special Compensation.

Since you're not getting any help here, you might want to try contacting an official at your local VFW for direction.

The American Legion also helps vets in this area. Call the local post and they'll probably refer you to someone in their state office.