I would like to release a plugin to Poggit. However, softdepend includes plugins that have not been released to Poggit. Does this violate the Poggit submission rule B5?
Actually it does not, as the plugin can operate without that plugin it is not a dependency, a dependency is something the plugin depends on and without it it cannot work. (Sorry it’s bit late just seen the time stamps)
However, you may need to declare the soft dependencies depending on what role they take in the plugin. For example, you have multiple economy plugins in support, and at least one economy plugin is dependent in order to make the plugin functional, then, you will need to state the plugins under "softdepend" category in plugin.yml.