So basically, it should be legal made a custom version of Workbench using these WB versions of Ten on Ten to distribute free?
Definitely not. BTTR asked for permission to distribute for every single package on their site. This is an exclusive permission for BTTR, it does not apply to anyone else. You are allowed to download the packages for free from their site, but you are not allowed to upload them anywhere else. Removing parts of a package and distributing the rest is an even worse violation of the rights.
