As you may have suspected another extension point that must be implemented is the learner and monitor interfaces. All the information you need to redirect to these pages should have been stored in the tool adapter's tables by the time you get to this point. So it should simply be a matter of constructing the learner and monitor URL based on the save parameters and then redirecting the user when the request is made.
Export Learning Design
How to implement export and import tool contentTo export a LAMS learning design, the authoring tool content needs to be serialised into a file so it can be imported again later in a different context. LAMS will go through a sequence and call each tool to output its tool content. This is made a bit more complicated for tool adapter tools, since they do not have the content stored locally, they only have an external content id. When the call is made to export the tool adapter content they have to call the external tool adapter servlet to request the content in a server to server call.
You will not need the customCSV for this so long as you saved the info in the customCSV in the LAMS tool content instance object, you will only need to retrieve the external tool adapter servlet url, and then add the parameters from the saved tool content.
Take note that you will need to handle the case where there is no external tool content (ie the authoring page for the external tool was never opened or saved).