I don't think that there is a vehicle that will give you direct access to the developers or HRs to ask specific questions as , with the numbers of active users for the game, this would not really be practical. I am also not sure how much information the developers or HRs will reveal to the user base as some of this may well be classified, so you may have to draw your own conclusions. There will probably be a number of threads in the Tactics forum written by experienced users that will throw some light on your questions.
CA ( Current Ability ) is a numerical value from 1-200 allocated at the start of the game and is the researcher's opinion of the current ability of the player. The attributes that you see on the player's screen make up the CA figure with those attributes that are important for a players role having a higher weighting that attributes that are not critical for his role- like tackling as you mention above . There are also a number of hidden mental attributes that contribute to the CA, thereby making the overall calculation pretty complex.
PA ( Potential Ability ) is a numerical value also from 1-200 allocated by the researchers at the start of a new save and will normally be a higher value that the CA meaning that the player has the option to improve his CA till it reaches the PA value and from there he cannot improve. The PA is a fixed ceiling and cannot be increased once the game has started. Players ability to improve will depend on age, experience, game time, training and coaching and the attributes of the coaching staff.
CA and PA are not shown numerically in the game but can be accessed using an editor. In the game these are expressed by the star system which is best to be used a a guide only as it can be unreliable depending on who gives the report.