The way they've dealt with the Fabregas thing is terribly amateurish. They haven't just lost Fergie, they have also lost David Gill. This is a completely different management set up now and I can not see them matching up to the previous one.
The good thing is that Moyes has sacked Fergie's trusted coaches now and given that Fergie had been delegating day-to-day coaching responsibilities to them for a long time, I don't think, he'll be too keen to take over, temporarily, if Moyes gets sacked.