I thought I had read this somewhere (and I am unable to find it again and may have this backwards or totally had a hallucination)...

Is it correct that OL players with a higher STRENGTH attribute do better blocking for the RUN while those with a higher BLOCKING attribute do better protecting the pass? Conversely, is the same true with DL (STRENGTH v. RUN and TACKLE v. PASS)?

That is true for the OL. I don't think that is the case for the DL, though. The only function the DL has on a pass play is rushing the QB. The LBs are assigned to the RBs and the TE, and the CBs are assigned to the WRs.

True on pass play possibly. But also possible that stregth is needed to stop a rushing rb. ? Unknown ? but i do like strong DL's.
Ok young coaches. The most important attribute in every position is ............................Durability - Roflmao :)(there is possiblity I might be kidding :).
Oh, and I know my spelling sucks

I believe that STR is the #1 attribute in a pass rusher.

There are numerous theories and educated guesses out there. Some are well thought out and logical. At the end of the day though no one knows for sure.