Yes, Linux/BSD is a free and open-source operating system.
Both are open-source projects but with different licenses that is Linux is based on GPL license and BSD is based on BSD license, also Linux is founded by Linus Torvalds and BSD is founded by University of California(Berkeley).
Referring to device official CD or webpage which you can download and install drivers from source.
Directly you can download and simply install any type of programs from package managers by either console or front-end environment.
There are third party apps and firmwares which can be use to connect your devices to share data between them.
Yes, It's highly customizable compare to other operating systems depending on different desktop environments such as KDE, Gnome, Xfce & etc.
Yes, Linux/BSD is highly portable so It can be launch on any device.
Usually the latest version of Linux/BSD kernel support many of new IT brands such as routers, Bluetooth, USB 3 & etc.
There are several open-source media formats such as FLACC, Ogg, mkv & etc. via codecs for watching movies and listening to musics.
WebM format by Google Inc which is contained of two open-source media formats such as Ogg(audio) and Theora(video) that is included of any new Linux/BSD distributions as HTML5 technology.
Yes, There are plenty of 2D and 3D video games designed for Linux/BSD so Installation of graphics drivers are strongly recommended.
Yes, Linux/BSD can play 3D movies and formats via third party applications.
No, viruses and worms are designed to work only on microsoft windows products.
Yes, It is absolutely possible.