Also another thing.
Throught the files of the vanilla version of GPDX it was discovered that Rosalina and Metal Mario were already in the base game, way before their update was released.
This is true because Rosalina and MM have almost all their game files inside the data, including voice and models but they are missing some icons.
This is way i was able to obtain Rosalina's voice with just the base game, because her files were still there.
Furthermore according to ID data codes , her and MM were added BEFORE Bowser Jr. was added to the game, and the latter ended up being unlockeable in the base game.
This is placeholder image for Rosalina inside the files.
And this all makes sense now, and it explains why Rosalina and Metal Mario by consecuence (but its more relevant for Rosalina) use their respective MK7 voice clips.
They were planned and added when MK8 wasn't a thing , so they straight up used MK7 content ... unlike Daisy for example who uses her MK8 voice clips.
It all connects now, but im glad because Rosalina deserved her MK7 voice in an HD Mario Kart so i can't complain at all.
More over it kinda connects to Namco Bandai as well.
Smash and GPDX use Kerri's voice ... both are games that in which Namco took over ... i see a pattern here, they seem to prefer that portrayal for Rosalina/Rosetta and even if it's not even confirmed id like to believe so.