We will add item.text  as mapping to ElementDefinition.label We will note that extensions that allow a context of both Questionnaire.item and ElementDefinition should propagate. We will remove item.type as something that can be automatically populated, but will note the correspondence and indicate that the mappings should align - and note that the target profiles for Reference or canonical should propagate to the appropriate Questionnaire.item extension. We will add language warning about the use of definition in that client systems won't necessarily recognize/process the definition and thus may not render or capture data against the questionnaire correctly.  We will also define a new optional 0..1 extension on Questionnaire and mark it as 'mustSupport' in our base SDC profile that indicates that the Questionnaire relies on definitions to populate some of its item properties (and thus that clients that can't retrieve the definitions can't safely handle the Questionnaire).