Potential challenge with the seatpost question is that the seatpost has to match your stem, now that can be tenuous in some cases (pantographed titanium stem from the frame manufacturer, titanium seatpost) but there has to be a relationship. A Fizik carbon post is a very nice post - but what's the headset diameter/steerer and therefore stem going to be? In my experience you need to nail down the stem choice first.
Potential challenge with the seatpost question is that the seatpost has to match your stem, now that can be tenuous in some cases (pantographed titanium stem from the frame manufacturer, titanium seatpost) but there has to be a relationship. A Fizik carbon post is a very nice post - but what's the headset diameter/steerer and therefore stem going to be? In my experience you need to nail down the stem choice first.