CM11 - chmod and chown on internal sdcard not working
the chmod and chown binaries you are using there are from the android toolbox and are pretty lightweight. You can use more powerful binaries from busybox. Maybe this solves your problem as I also encountered issues with the small set of features of the toolbox ultilities.

busybox chmod 075 /storage/emulated/0/TitaniumBackup/somebackupfile.tar.gz
busybox chown system /storage/emulated/0/TitaniumBackup/somebackupfile.tar.gz




EDIT: Sometimes it just helps reading carefully. Didn't get that your sdcard is an emulated sdcard which is implemented permissionless. This means it is right behavior that chmod/chown do not work at all here: 

From: https://source.android.com/devices/storage/config.html

Devices may provide external storage by emulating a case-insensitive, permissionless filesystem backed by internal storage.