Ji bai acts like the vampire form has it's own personality/mind/thoughts but from the WN I can confirm that isn't the case, just that he was harshly educated as a vampire, and follows many of those noble lessons. The second chapter of the WN has him explain how those habits and mannerisms have bled into his ever day life, i.e. being prim and proper with folding his clothes, even though before he would have just kept his room messy.