I have a question about “Tubepress Pro”.
The single site license for TubePress Pro has a limitation of one website, but if I use that plugin on the main domain and additionally place another WordPress in a directory below the hierarchy, it will be Are you done?
As long as your subdirectories are still part of one website, then you may use the single-site license of TubePress Pro. For instance, if you purchase the single-site license for use on example.com, that license would cover example.com, example.com/foo and example.com/bar. For detailed differences between the single-site and developer’s licenses of TubePress Pro, please see the full texts of each here.