So first I would suggest settings closer to 0db:
FR +1
C +4.5
FL +1
SR 0
SL 0
SW I would leave at -6 but I like a lot of bass.
I'm guessing that you are just hearing things that your old setup didn't pick up. You have to remember that most voices aren't recorded when the scene is shot but afterward in a studio where the actor is "talking into a mic".
I'll have to go back and watch those movies again and see if I notice anything. The difference between DD/LPCM and PLII is that DD/LPCM are individual audio channels for each speaker. With PLII you have 2 channels and the others are matrixed out of them. You may not like the sound of the speakers, did you audition a lot before you picked what you have?
As far as the crossover setting you are right that it more deals with the bass frequencies, the thing you need to remember is that when you set it up at 120Hz or even 100Hz you start to "localize" the bass sounds as those frequencies aren't omni directional like lower bass notes. If you set it too high you will even start to hear male voices come from your sub woofer

I would probably up it to 100Hz and see if that helps.
Also do you have any of the effects on on the receiver? IE the concert hall setting or anything? Make sure that is all off.