The .project file has be exported, too. Because the StandaloneSetup of the MWE2 only register a bundle to it's PlatformResourceMap if the Bundle is a .jar or contains a .project file.

plugins/org.yakindu.base.types/build.properties

@@ -9,7 +9,8 @@ bin.includes = .,\
                META-INF/,\
                plugin.xml,\
                plugin.properties,\
-               schema/
+               schema/,\
+               .project
 jars.compile.order = .
 source.. = src/,\
            src-gen/