Borderlands 2 co-op within same platform family? [duplicate]

The verdict is in. If you are wanting to play via local area network, the answer is no. You can still play multiplayer.

To directly quote the fine print, at the bottom of the official Xbox page on multiplayer;

Multiplayer between Xbox 360 and Xbox One not supported.

This is why it took the release of Xbox 360 emulation, to support Xbox 360 games on the Xbox One, rather then being able to support the older generation of games from release.

That said, you do have the option of Xbox emulation. With a 360 copy of Borderlands 2, you will still be able play together, online. There is one catch: It has not been released yet. Microsoft have promised "100 games this fall, and hundreds of games over the next months". Once they have released backwards compatibility support for this title, your in the clear.

Cross-platform play and the expected release cycle of games are advertised on the Xbox website, on the page detailing Backwards Compatability.

I was unsure, myself, if this also meant local area network. I contacted Microsoft Support, directly, and asked them. Unfourtunetly, to quote "Vinz" at Microsoft Support:

Yes, you need to access Live.

TL,DR: If you use a 360 copy of the game on Xbox One, you can still play with other 360 consoles online. Other then that, there are a few restrictions that prevent multiplayer between the two consoles.