1. Maybe. Depends on your seatpost. If it's a two-bolt style, you might have trouble. Single bolt, less trouble. Ancient-style seat-guts on a post style, probably easy as hell.

2. It'll be super comfortable for the first 2 miles. Like riding a bike on the arm of your sofa. After a while it might cause trouble. Like riding a bike the arm of your sofa.

3. Some folks I know ride BMX race seats all the time.

4. I like the Selle Italia Turbo Matic.

5. Because they use them differently. A seat supports your weight entirely. When a BMX kid sits, that's what he's doing. A saddle only supports you somewhat; your arms and legs are still doing a lot of the work (like on a horse, also a saddle).

6. Pegs rule. I am fantasizing about an old track frame with a coaster brake, platform pedals, risers, and pegs.