Q1: Can't quite recall the capacity (2 gallons is a wild guess), but you can drain the majority of it using the drain screw at the base of the radiator. Any old 50/50 antifreeze mix will do. When you pop the alternator out, there will be a little mess, but nothing huge -- a regular drop pan worked fine for me.
Q2: Remove fan, remove main belt (need set of bigger torx bits and a breaker bar), unbolt power steering pump so you can move it forward to get to the pulley screws easier, remove deflection pulley (in front of the alternator) (this is the pulley mounted with the bolts that are a pain to get to), remove the bolts on the face of the alternator housing and pop the alternator out.
Q3: Expect it to take most of the night mainly because of the pulley mount bolts.
Odd tools: Tool to hold the fan still using the pulley bolts (can maybe rent from Autozone or make a ghetto one like mine -- shown here and here), breaker bar and torx bit for the belt tensioner (shown here), and the crows' foot wrench set (shown here).