Noob Question: Classes

[Diaz Ex Machina]

Is it possible to completely overwrite the existing vanilla versions of Barbarian, Monk, and Rogue with their Unchained counterparts WITHOUT enabling Pathfinder Unchained in the options?
I'm trying to do this with the Barbarian, created a new class simply called "Barbarian" with the Unchained abilities. Everything works fine, until I try to replace the core Barbarian class; when I do it gives me this warning whenever I enter or exit the class selection window:

This is because my new class is treated as both an alternative and a parent class for the two Barbarian classes:

What can I do? Do I have to hide/preclude the original class? Or is it just an impossible thing what I'm trying to achieve?
Thank you in advance for your help and time.

EDIT 1: I also get this error now:


EDIT 2: I'm trying also to create a new prestige class, but I keep getting this warning when adding its levels to my hero:

It also doesn't give any HD or anything else.

EDIT 3:Solved the prestige class problem, I had the wrong Source checked...