xDD!!
Weeell, I'd say not mandatory. x3 I'm pansexual! Pretty much all pansexuality means is that it's more broad than bisexuality which still accepts a gender binary. Pansexuals on the other hand believe in either more genders than the usual male/female binary or don't even believe in gender at all. I'm the sort that doesn't even believe in gender. But the best way I can sum it up is "love knows no gender."
/gender studies
Of course, for the pervy character pansexuality DOES certainly make it so that NO CHARACTER IS SAFE from the bow chika wow wow! xDD Whereas most pervy characters at least have boundaries in what sex they're attracted too, well...a pervy pansexual? Male, female, transgendered, transexual...it's all good!
Thus, all characters should run.