Hi Jason,
Alternative BOM can be created for a same material and there is no effect in material master. As the header material is same and components/qty only differs.
Traceability can be activated through ECM. But some setting is required.
If you want to see the change report you can see through CS80. Or you can see from BOM Environment-> change management.
And you can create 99 alternatives for a particular material.
Regards,
Krishnendu.