I've watched the trailer over and over and analysed each and every frame and I believe it is indeed set after DMC2.
The biggest give away for this is Dante riding the motorcycle at the end as DMC2 ended with Dante riding a motorcycle into Hell, but what really supports this theory is the destroyed city around Dante as he rides down the road.
The buildings are clearly torn apart with burned vehicles on the road and what not and it doesn't look like recent damage, what further supports this is that in that scene those demonic tentacles Nero is seen fighting are nowhere to be seen.
Also if you'll look behind Dante at a certain time you'll see what appears to be a destroyed skyscraper of sorts:
(You can barely see it in the animated gif)
I think this is the tower where the portal opened in DMC2 or what's left of it:
I believe that the final scene in the trailer is indeed Dante returning from Hell and racing down the streets of Uroboros City on Dumary Island.
Some are saying that it's not set after DMC2 cause Itsuno said that it's a direct sequel to DMC4, well I also heard that it takes place a few years after DMC4 and it being called DMC5 is probably what he meant by that.
Also he may have been pointing out that it's a direct sequel to DMC4 so that new players don't mistake it for a DmC sequel.
Plus it can double as a marketing tactic as well, if he said it takes place after DMC2, that would cause newer players to play DMC2 to catch up and get a bad taste in their mouths from the games poor quality, discouraging them from playing DMC5, they're likely to want more after playing DMC4 though.
Now my theory on "Where is Rebellion?", consider this:
I believe that the motorcycle itself IS Rebellion, maybe while in Hell, the standard motorcycle was damaged and Dante merged it with Rebellion's power to create the "Rebellicycle" if you will.