Wow I missed that. I would think PnR D IQ would determine if TE player executes the defense correctly, meaning are they in the proper position. Will a big hedge or not or will a guard know whether to go over/under a screen etc.
Help D IQ probably has to do with how active a help defender is when there are defensive breakdowns and whether he knows when to help and when to stay at home.
Pass perception? You got me. Maybe how well a player gets in the passing lanes? Or how aware a player is of passes near him?
These sound like great additions.