i think you arent getting answers because everything is still in very gray areas with the new engine.
ill give it a shot, but these are mostly semi educated guesses.
1) it should be just OL/DL with modifiers based on how many players are attached to "line" on defense.
2) the advanced charts work because some players have higher in game ratings at OT than at OG/C. If a guy is better suited for OT, then your line grouping rating is higher. same with the defensive side.
3) This is an excellent question. i have no clue.
4) in the BETA things seemed to play pretty close to ratings in 2.0. the biggest difference i noticed was that ath seemed to jump up into the core for just about every position, but moreso the RB spot than anything else. i would put ath near the top of the chart for all RBs with speed, then STR for inside runs and elu for outside runs.
5) For the LBs-- if they are set to line, they always rush the passer/play the run, and are included in the OL vs DL matchup. if they are set to cover, they are in the secondary match ups as the play progresses. i am not sure about the blitz % but i think it has to do with how often a player who is set to cover joins in the DL grouping.