Thank you for your work, we're very fond of GD CPT Tools.
We've found 2 things that can possible be bugs:
1. "Post edit column" parameter in adding/editing taxonomy UI. If we understand correctly, "yes" value must lead to addition of a new column in taxonomy terms list table. But turning it on or off seems to not affecting anything.
2. Terms list widget. Right now it's working only with hierarchical taxonomies (an argument is setted in "true" in widget's code). We're fixing it by adding new checkbox in widget's form, and a new variable in it's code. But it's worth to fix in main repository, as i think.