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Seriously? Please don't include something like that, its obvious that you are, theres no need to state it.
#1: Don't. We don't need to help you navigate through development because honestly you shouldn't be doing this. While C is not requires it is
highly recommended since most tutorials/documents are written in C or with C in mind. You could write an OS in another language, but you will still need to learn assembly, which to learn well is an undertaking on its own.
#2: The right tools. Figure out the language to use first. Then look on the wiki.
#3: As I said and others have said, you don't need C. Though you will probably want to know it.
#4: Basically what you're looking at: You must learn how to program in at least assembly. Then you must become very good at it. Then you must learn how the low-level parts of the computer operate, and learn about architecture specific operations. Once this is complete, you must start making the OS, which is already damn hard even in C. Then you must make it work well (MMU, Multitasking, FS's, hardware, UI, etc).
Of course, the feasibility much depends on what you know - what languages do you know, and how much about the computer's operations do you know?
My advice: Try an easier project.
I know that I'm just reiterating what others have already said, but I felt like I wanted to post this anyway.
-JL