1) Bootable CD: Any CD recording software able to burn a CD image, Bootable USB: for instance unetbootin, but check the guide on the Ubuntu website.
2) Usually on Linux based systems, executable programs don't have a special file ending, so no .exe. If you intend to run Windows programs, there exists a compatibility layer called WINE that can run many Windows programs, but by far not all.
3) Many, but not all. Check the WINE Appdb on the WINE website.
4) There exists nearly no viruses for Linux. Nevertheless, if you want to search for Windows viruses, there are some virus scanners for Linux, most famous is probably clamav
5) No. Linux is the Kernel that is used by Ubuntu. Many of the programs that make up Ubuntu are from the GNU project, therefore Ubuntu is a GNU/Linux distribution. Think of Linux as the kernel32.dll and nearly all drivers of Ubuntu :-)
6) I don't know about Real Player, but for VLC exists a Linux version (available in the Software Center of Ubuntu) - of course without the .exe...