I don't expect Murray or Djoko to last as long as Federer. Neither is quite as talented and both depend more on physical fitness than Federer does. Once they begin to lose a step they will drop faster than Federer did. But, I do think they will win a majority of the slams in the next 2 maybe 3 years.
Pretty much. On clay I would see Murray as still only being the 4th or 5th best, and on grass see Djokovic as only the 4th best or so . On hard courts, all speeds, Djokovic and Murray will be the ones to beat.
They might become the favorites for AO and USO for the next few years. But RG and Wimbledon finals will still be a big task for them to get to ...especially if Rafa comeback hungry
if Nadal comes back strong my predictions is the most likely French finals would be Nadal vs Djokovic and most likely Wimbledon finals would be Murray vs Nadal over then next few years. We will see though.