I’m stumped...I setup a custom WAB app (Dev Edition), including the out of the box Edit widget and a custom widget. My Feature Layer has editing enabled and it's functional in the Web Map. When I share it to my custom WAB template and click on the Edit widget I get this message: Feature creation is disabled for all layers. No issues with a standard WAB template. Ideas?
Update: This has been isolated to an issue with the WAB Export As Template and the Edit widget. It's identified as a bug with Esri now. The short-term solution is to build the app with a defined web map. More to come on a long-term resolution with a template-based workflow.
This is a reported bug (BUG-000087970). It's been "in process" for a year now, but the status shows as "In Product Plan" and it's now ranked as a "High" priority. Hopefully that's in line with your timeframe.