It logical that if they Don't show corrupt version in the character description they will not show it in the cg.
So Don't have it in cg is not a increass of argument against corruption i think it possible for some indice :
1) In the past corruption game they have all main girl corrupt
2) with every new corrupion game they give less and less spoil in dessire they spoil all;in frontier they give all girl in two form but one girl have a surprise form,
in ragnarok they give all girl normal form and corrupt form but hiden the chaos form of 4 out 5 heroine
3) i think it will have a least two ending by girl one law route and another chaos route so it logical to think chao route will be corrupt form.
with all that i thing it possible that all heroine may have a corrupt but i Don't say it likely
i thing they have 75% of probability that they Don't and 24,999% they have and 0,001 that more that 5 girl will have corruption
in the end it possible that we have 5 corruption but unlikly but 25 is not so bad