I've always thought that the leadership of the club shat itself after we won the league in 2012 - clearly ahead of schedule.
Not sure about Begiristain but Soriano was definitely in situ as part of the 'get Guardiola' plan - I only remember that because of Bobby Manc's rant about how he should have stuck to running an airline.
The club had clearly decided that they were going all in for Pep at some point during Mancini's time at the club and I think they were worried about how they'd look giving Mancini the bullet if he'd started to build on the 2 trophies he'd won in 2 years... simple / underhanded method of dealing with the situation... hamstring Mancini in the transfer market which they knew would make him lose his rag, giving them an excuse to get rid of him, regardless of if it meant having to have a stand in (Manuel the laziest man in football) for a period until Pep was available.
I've always felt that the leaks about Mancini's position on the evening before and morning of the 2013 FA Cup final were deliberate sabotage of the first team by the hierarchy of the club.
Having been a season ticket holder since the middle of the Swales era it seems somewhat bizarre to say that turning up for a cup final at Wembley, 12 months after winning the league, I witnessed the worst pre-match atmosphere amongst City supporters in my entire time as a supporter.