There are at least 4 approaches that address the first question: 

1) The 'life' and 'death' in question are not that of this world, but of the next (Tosfos among others).

2) 'צדיק' and 'רשע' in this context don't mean 'righteous' and 'wicked', but rather 'exonerated' and 'condemned' (as in Devarim 25:1). (Rabbeinu Nissim, Rashba's first approach, Tosfos Rid, Mordechai, Ramban)

3) "רשעים גמורין" means absolutely 100% wicked (Sefer Hachinuch, Pnei Yehoshua). Very few people fall into this category, and it's impossible to know with certainty if any particular individual does, even if they have committed the most heinous crimes.

4) "מיתה" means a shortening of one's life from the length that had previously been decreed (Raavad, Rif).