Is there any way that set the application Icon and Name from an external resource such as an image which embedded inside the assets/ folder in the project?
No.
Or is there any way that let us set icon and name of app without using AndroidManifest.xml file?
No.
For your activities, you can override the title and/or icon used in the action bar or title bar, if that is your actual objective. However, you cannot change the values used for things like the home screen launcher icon or your app's entry in the application list in Settings.