Spot on. Only thing missed was potential price of the patents (which arguably that price will pay for core sale taxes). Only real bet on yahoo stock right now is whether the board can avoid some of those taxes on an alibaba or yahoo Japan sale.
Sum of parts for yahoo is a terrible way to calculate it's actual value. If you look at the balance sheet you'll see billions in deferred taxes. That relates directly towards selling alibaba and yahoo Japan in the open market. The play on yahoo now will be is if yahoo board members can save money on those taxes. If you think they can, you win. If not, stock is trading roughly around the fair price.
1: http://www.agweb.com/mobile/land/farmland-value-guide/