I have added your requests to the existing issue in Github tracking feature requests for Gateway Quizzes (https://github.com/openwebwork/webwork2/issues/1156).
You're right in that it is almost certainly too late to get these things into 2.16, since we are expecting a release candidate this week. In fact, it's more likely that most of this will be considered for WeBWorK 3.0, as the focus this Summer is going to be on overhauling the WeBWorK interface with the idea of releasing a new version.
Thanks, and that was the post I think I saw about this, mostly just similar ideas but putting them into one place.