Some of those prices are crazy to me.
This is where it is time for give and take related value or for some durability(but this is WW talk for now)
For under 50 you could get a carbon seat weighing 90-100g. ex.
http://www.aliexpress.com/item/Full-carbon-saddle-bicycle-saddle-velo-sillin-bicicleta-specialized-mountain-bike-seat-saddle-carbon-saddle-front/32232911782.htmlAn alternative to extralite:
http://shop.shift-up.eu/fr/product/qr15-axle/?lang=en&lang-id=1 front
http://shop.shift-up.eu/product/x12-rear-axle/ rear
Something not mentioned here for lighter weight...racing tires....like Stan's Crow or Raven? or the new Schwalbe Thunder Burt....this would put you in the 16lbs range.
Again, will be interesting to hear your thoughts on the lighter weight in your races...I say this because we probably carry more weight that could be shed.
Short race...an hr or less, one shouldn't need much liquid during the race...but we have giant water bottles(or 2) or a camel back.