Okay I was able to disable strict-mode using by defining the system-property in JBoss. With that and fixing up some of the imports I was able to reduce the compilation errors shown in the workbench to just a couple.

The errors I get now are:

Error importing : 'com.mycompany.MyClassUtils'
Error importing : 'org.apache.commons.lang3.time.DateUtils'
[ function isEventOnSameDay (line:18): Only a type can be imported. com.mycompany.MyClassUtils resolves to a package
isEventOnSameDay (line:24): Only a type can be imported. org.apache.commons.lang3.time.DateUtils resolves to a package
isEventOnSameDay (line:36): DateUtils cannot be resolved
isEventOnSameDay (line:37): DateUtils cannot be resolved
 ]

The MyClassUtils is a class defined in the same project as the DRL files. Therefore, assuming the workbench is also compiling/loading the java files in the classloader it should resolve without issue. The DateUtils class is a maven dependency and I assume should be loaded by the workbench as well? Why would the compiler see these classes as packages?