Let's say a wildblooded sorcerer has the warped bloodline associated with the aberrant bloodline, can he choose the aberrant bloodrager bloodline and keep warped for sorcerer?
yes, the warped bloodline is still the aberrant bloodline, just with a few changes, but it's still based as aberrant. You're having an archetype modify the bloodline. thus going bloodrager aberrant is keeping the same bloodline.