FSG are more to blame than anyone for those signings, they were the ones that wanted to implement moneyball into the premier league, so they hired their stats man (Commoli) after listening to the advice from Billy Beane. They told Commoli to find value in the market, so he looked through all the stats and pulled out those players because statistically they were undervalued.
Downing because he crossed the most, Henderson because he created the most chances of any young player, Adam for his chance creation stats and assists, Suarez for his goals and Enrique because he was the most defensively solid left back in the league statistically. FSG wanted to try this strategy, thats why they lost all their money, because money ball means nothing in football.