Progress Update: I've moved all of the basic functionality of the extensions into the regular parts of IDLE, including menus and keyboard shortcuts. parenmatch and codecontext have all of their settings now in the Highlighting settings tab. I have added theme elements for both, as that was both easier and more in-line with what the rest of the IDLE settings were doing than trying to have a separate color-picker for them. The attached image is what it looks like.

What is left for me to do: add the configuration dialogs and proper setting saving for the remaining extensions/modules. Change help texts. Once the configdialog changes patch (#30779) goes through, I will of course, need to fix anything both touch, but that shouldn't be too difficult.