No, of course not. For example processes, memory-pages, environment variables and semaphores are not treated as files.
You don't edit inodes manually. They are managed by the file system driver.
One could find information online regarding Linux file servers at the HowToForge website. The site covers everything one would need to know about Linux file servers.
The pros and cons of the Linux file system include the quote saying "On a UNIX system, everything is a file, if something is not a file, it is a process". You can consider this either a pro or a con.
Most file systems are treated almost exactly like drivers or kernel modules. Some can also be implemented in userspace (ex. FUSE).
The first file system Linux supported was the MINIX file system.
There is no set file manager in linux. Examples of Linux file managers include but: Nautilus (GNOME) Thunar (XFCE) Dolphin (KDE)
The Linux VFS (Virtual File System) may be thought of as a sort of interface between the Linux kernel and the mounted file systems. There can be many different file system types mounted simultaneously and VFS allows the Linux kernel to see and address them all in a similar way. This provides Linux with a great deal of flexibility. [JMH]
ext3 is the default file system for Red Hat Enterprise Linux.
There are programs you can download that will read Linux file systems. Common file systems are ext2 and ext3.
Traditionally in /usr/src/linux.
Yes. Just about everything to do with Linux on the command line is case sensitive, including commands and file names.
There is no "the startup file" in Linux; depending on the type of system, there may not be any files at all. The Linux boot process has a number of steps, many of which are optional or have alternative implementations.