Soak the BB cup with Liquid Wrench (or similar), let sit while it penetrates, then clamp the flats on the cup in a decent-sized bench vise and use the leverage of the whole frame to unscrew. Keep in mind that the right cups are likely reverse-threaded, so you need to spin them clockwise to remove them.
For the seatpost, try the same method listed above, clamping the exposed section of seatpost. Crushing it will be necessary, but be careful not to break it making it useless.
No luck? Try heating the post with a propane torch until it's glowing dark red under the flame. Carefully re-apply penetrating oil, and try clamping and twisting again.
No luck? Let cool, cap the top of the seatpost with duct tape, flip the bike over, pour household ammonia down the seattube through the BB shell, and let sit overnight. Drain and try the clamp & twist thing again the next day.