Looks like quite a project there
Honestly, most of those questions can't be answered in any definite way - but if hints are wanted, I can contribute some:
@1) Yes, you can. A lot of servers run GNU/Linux, and there's always a demand for skilled people. And there's a growing market for GNU/Linux on the desktop as well. Look at http://lxer.com
for a couple of days (or maybe weeks) to get an impression (and a lot of useful links and hints on resources).
@2) See 1; additionally, think of businesses moving their servers to Linux. Think of education (the people there are increasingly aware of the fact that GNU/Linux cannot only save their day after another M$ blunder, but also loads of money). And from what I see around me (people switching to GNU/Linux simply because they like it - normal users, not necessarily geeks), this is just the beginning. As a matter of fact, everything that can be done with computers can be done with GNU/Linux. And more and more, it actually *is* done with GNU/Linux!
@3) The more you know, the better. If you consider making a professional career, some coding skills are more or less mandatory (if you're not trying the "consulting" way of things [going all "meta" without having a real idea of the things you're talking about] - I don't recommend that, though; it's not a healthy way in the GNU/Linux world). And obviously, M$-only skills are not nil, but not really helpful. But what you really need depends on what you want to be able to do. Shell scripting, scripting, coding, even markup - the more you know the better. You can start with a very basic knowledge level, though, but again, if your want to earn money, you'll have to be able to handle things properly and work your way through problems by yourself. Hands-on is inavoidable. Beards, OTOH, are optional.
@4) Look at: http://www.lpi.org/
- and search the web for Linux certification
, you'll get any information you'll ever want and need.
@5) No need to specialise; in fact, the more you know about different approaches, the better you'll be able to judge the suitability of a certain distribution for a special task at hand. I myself are totally biased towards Debian
and its decendants, but others may feel otherwise - which is absolutely fine by me. As learning tools, I'd recommend Debian
if you want something that's made a major impact in a very short time), Slackware
(or maybe Zenwalk
for an easier start while not losing most of the advantages of Slack
) and Gentoo
(even though my personal experience with the latter is a bit sobering, but I admit that I've learned a lot from trying to use it - especially about my personal limitations
). If you don't like the hands-on approach (which I'd judge rather disappointing, really - do you want to get into it or not?!), there are a lot of others that offer more "ease of use", but if you want to learn, I'd say: Do that, then.
@6) *IF* you've done what you described, I'd say you'll know: If you do eight full months of dedicated learning and research, you'll be sure of what to do next. If not - well, you'll still be a lot better placed for IT work of any kind! In fact, learning GNU/Linux is just about the best way to learn about computing and every related subject (IMHO).
That said, the first thing would be to get a distro working on a box and look thoroughly at how things are done in GNU/Linux. Again, Debian
'll do just fine (and so will all the other so-called "tough" ones). I wouldn't say a course is necessary (or even helpful); doing things is a lot better. If you get stuck, seek help on the net.