Everything I've seen and heard about this decision suggests RGG Studio see Tupac as one of their talent - they're not putting Tupac in their game, they're putting who they imagine Tupac would be 30 years after his murder in it.
At that point it's barely an homage to the man. It's someone else.
LittleKuriboh
Stranger Than Heaven's Tupac Shakur cameo will "try to envision who Tupac might be now", RGG Studio head Masayoshi Yokoyama has said.