For some reason, when I perform the individual map's first munge (the first use of VisualMunge.exe inside the map's folder), the process ends very quickly (which I KNOW it shouldn't) and the map is not able to load inside battlefront 2. Has anyone else encountered this issue? How should I go about fixing it?

Welcome to gametoast. That is most likely because you are using the mod tools on a modern machine. The "vista munge fix" can be found in the everything you need thread, it will probably fix your issue.