I am an author on Themeforest mostly, but many clients ask if I sell some of my Joomla extensions separately. I want to start doing that as my extensions got to a high quality level.
The Envato regulations says that I have to ask a layer or the copyright owner that is me, do you think there is something more than this to do it?
As long as you don’t sell these Joomla extensions here on the marketplace, everything is fine. Envato has got nothing to do with this.
If you would like to sell your joomla components that you created for your themeforest themes, then listing them here on CodeCanyon is totally fine.
Go for it and be sure to link between your items on the different marketplaces to increase sales (eg: “like this joomla extension? get it with my theme here” or “like the extensions in this joomla theme? buy them individually over here”) .