There is no Windows 8.
Windows 8 has new interface that has all your apps in one place.
Microsoft Windows 8 will suceed windows 7.
Windows 7.
Windows Calender is included with Windows Vista. It is not included with Windows 7 or 8, but can be copied over to Windows 7 and 8 from Windows Vista.
Internet Explorer 8 is included by default in Windows 7.
In general, yes; most software that runs under windows 7 will run under windows 8.
Get a USB Flash Drive and get files from Windows 7 and transfer to Windows 8.
Yes. Windows 8.
Windows 7
Because windows 8 themes are basically still windows 7 themes, they just have windows 8 graphics as the background colour. Thier coding is still the same.
If you mean "Visual Styles" by saying "Themes", the extensions of windows 7 and windows 8 visual styles are different. That makes it almost impossible to install windows 7 visual styles on windows 8. There may be other alternatives for it.
Nope, especially since there is no Windows 8 yet.