This is a good thread with sensible questions and a lot of reasonable answers. We should do these kinds of beginners guide threads on a semi regular basis, with ones explaining tactics, the importance of the slipstream, the many unwritten (and often inconsistent) rules of conduct in the peloton, etc.
It's perfectly normal for someone coming to cycling from other sports to have an assumption in the back of your head that fans will mostly think in terms of teams rather than individuals and that nationality will be the main factor in choosing who to support. And there is some element of that in cycling, particularly with those teams that have a relatively strong national identity. I suspect that most fans do keep at least an eye out for their "home" riders, all or most of them if they are from a small country with a small number of pros, or a subset if they are from a major cycling nation.
That said, teams have a much weaker identity and a much more tenuous existence than teams in other major sports. The closest equivants are some motor sports. Football clubs don't change their name to that of each new sponsor and then disappear entirely after four years. Individual riders tend to be supported for reasons that tend to be based on their perceived character as a rider - their style, bravery, tactics, etc - but there are few universals (a couple of years back we tried to come up with riders that everybody likes and there were very few contenders).
On the sprinters issue: For years there was one sprinter who was clearly in a class of his own, Cavendish. Now there are three very closely matched at the top - Cavendish, Kittel, Greipel. Kittel probably had the slightest of edges over Cavendish last year, but really, you couldn't reliably predict which of the three would win any given sprint. This year, who knows? Kittel may be on an upward trajectory relative to the others. Last year may just have been a slight blip for Cav and this year will be business as usual. We just don't know yet.