First of all, I've never seen an achievement server, but if people want to waste hours grinding on achievements by all means, let them. It sounds too boring for me.
I've been playing maybe 10 hours a week for the past month or so and I have managed to unlock 3 pyro, 2 medic and 1 heavy...
Lol, no its not. Its a joke. The sniper had to get back into the update somehow after the spy killed him. Is there any better way than this? It will be interesting to see what the last unlock winds up being, though.
edit: I meant yes, the picture is real, no, its not necessarily a bad sign.
If by drivable vehicle you mean a "battle-segway" then yes... yes they do. Otherwise, the gameplay wouldn't really work with vehicles, its better suited to closer range.