1. You should read manual o understand all properties, you will be able to set it up properly to suit your project well.
2. Minimum Android version requirements you set up in Intel XDK by setting the minimu Android API requirements.
3. This is not so important, you can set it to "no".
4. For this you also should read tutorials and understand them. You may need to set up some plugins, depends on your project. Build setings are the most important, and most of them are self explainable. And the last one are the icons and splash screen for your game. You simply upload pictures there.
5. It depends on your project needs - as I said above already.
6. Various plugins, are in various places... so again - depends on the plugin.
7. Well this is not enough to tell what is wrong. Probably you use some plugin which is not added.