As for the Rokuko who was currently with him, naturally it wasn't the real Rokuko.
Rokuko was the dungeon core transformed into human form, so it wasn't safe to bring her out of the dungeon.
This was one of the main reasons why he didn't have her come out in the first place.
So instead of having the main dungeon core come out, he had invested in a second improvement to the dungeon called the branch dungeon core system.
Right now, they were only able to create a single branch dungeon core, but that was enough for what they wanted to do.
Instead of using that branch dungeon core to create another dungeon, Lin Fan used it as a clone for Rokuko. So while the main dungeon core remained inside of the dungeon, she would be able to transfer her consciousness to this branch dungeon core and remain by his side in this body.
Of course, if anything were to happen in the main dungeon, she would be able to connect to the main dungeon core instantly.