Not going into adaptive versus responsive debate, can you point me to the use case you are trying to achieve?
File upload already supports camera capture on device if you set correct mime types in file upload edit dialog.
For #1, you can create and plug your own widget. A sample around how to do that is available here . In your widget you make your code conditional to show different control for different devices/browser types.
For #2, Offline form is on our roadmap, but currently we do not provide this capability OOTB.
Optimize the look and fell of the progress bar and widgets like calendar, numeric field, file upload etc... based on the device from where it get accessed. Eg: Change the numerical text field as slider
Offline support for Mobile. Eg: If the internet connectivity is not there in mobile, then save the form in the app (Phonegap) itself rather try to submit to server. This behavior is needed only for mobile devices.