The timing is certainly tight, but it really doesn't make any sense for it to be Alfred's fantasy. We're supplied with two independent verified indications that Bruce survived (the missing necklace and the autopilot patch, which Bruce outright lied about to witnesses to make it look like he was going to die), .
And the fact that somebody replaced the Bat-Signal on Gordon's roof.
There's no ambiguity here. All those epilogues happened, including the bit in Italy. And Bruce deliberately went to Florence so Alfred could see him there, just as he had always wanted to . . . .