I think the Room of Requirement works similar to a "search engine" of sorts, with the Room of Hidden Things (a state of the Room of Requirement) serving as it's database of things it can provide. The Room of Requirement is also capable of self-reconstruction and could perhaps connect to Hogwarts plumbing as Dumbledore once recalled a time he really needed the loo and found a restroom he was not familiar with.
I imagine if Harry really wanted to talk to his dead parents via the room, the room will probably just give him the Mirror of Erised to look into. Harry would not have specifically stated some means to talk to them spiritually or if they could talk back at all.
And that is pressuming the Mirror of Erised was returned into storage after HP&tPS and not relocated elsewhere or else the room will not be able to provide best results for Harry's desires.