Re: I don't see how in the World it's possible for this team to win less than 85 game
Well, if you want to analyze it by pitcher wins (and I wouldn't), I wouldn't call it conservative. I'd call it extremely optimistic. Last year we had two pitchers with double digit win figures. One of them (Arroyo 15-11) had an awful ERA (4.77) that was the same as (6-17) Harang. Even your "conservative" scenario has all pitchers #1-#5 at double digit wins. That's not a conservative scenario.
FWIW, there were 40 pitchers in the NL who won 10+ games last year. 15 teams of course. Only 24 NL pitchers had 12 or more wins (which is the minimum you are projecting for our #1 to #5 spots).
But it is spring and I am getting hopeful too . . . I think the pitching is pretty good but I don't know how the offense will be. It seems like they should be improved when I think about the positions and player development, but I remember some painful low scoring games after Dunn and Griffey departed.