Oxygen uses the DTDs/schemas provided by the DITA 1.2 specification for editing Learning specialization topics. It also uses the DITA Open Toolkit to publish the content to various output sources.
I cannot help you much in this regard because we are not using the Learning specializations internally. And there do not seem to be a lot of people who do, searching around (or asking questions on) the DITA Users List might be a good place to start:http://tech.groups.yahoo.com/group/dita-users/message/29486
It seems that using Interactions domain elements I should be able to generate xhtml (WebHelp) that allows a user to click on a set of possible answers to quiz questions that should provide instant feedback. Instead, whether in PDF (where it obviously should not work) or in WebHelp (where it theoretically should), the questions and accompanying feedback elements simply display with no interactivity. What is a good resource for details on how to set up these sorts of interactions?
No, learning topics are not translated in interactive HTML form controls. This was not the intended purpose from what I saw in a previous discussion on the DITA Users List (cannot find the thread now).
Actually this is quite hard to do, where would that feedback be sent and how would you identify the person who sent it? You need a PHP script running on a server with a database in order to store that information. You need each user to authenticate.
Our WebHelp with Feedback transformation does something like this. Each published topic has a feedback area at the bottom which can be used by users to comment on the read topic.
Probably the DITA 1.2 specification is about the place to start (and maybe the only place to start):http://docs.oasis-open.org/dita/v1.2/os/spec/archSpec-learningTraining.html#archspec-learningtraining
Also, some learning and training elements do not display at all in WebHelp (the lcTime sub-element for Duration in learning content overview topics, for example).
The DITA Open Toolkit XSLT processing may not handle properly all the Learning specialization elements.
Actually I added a bug for your problem about a year ago:https://github.com/dita-ot/dita-ot/issues/655
The issue points to a more detailed discussion on the DITA Users List.
I guess my primary question would be, where in oXygen or the DITA-OT are characteristics of these learning specialization topics/elements controlled and where can I learn more about how to implement them?
The DITA Open Toolkit applies a series of XSLT stylesheets on the DITA content, stylesheets which can be potentially changed and improved to match what you need.