Oh, well... To say the truth you wouldn't have to go as far as double or triple stop bends, you cannot do even a single string bend in classical position! For barré chords, on the other hand, I have always supported "old-school" style: Thumb behind the neck, first finger across all strings, little or no pressure from the thumb... In fact I try to keep the thumb behind the neck most of the time (bends not included).
This goes as far that sometimes I play some Hendrix tunes not grabbing the bass note with the thumb, despite it is theoretically more difficult!
But as I said, especially with electric guitar, there is no strictly right way to play it... It is just my personal problem!
Classical technique should never be underestimated though. I remember the first time I heard Segovia playing Bach, it was incredible.
As your description says, we rock guitarists are mostly pentatonic paupers