1) Yes, star rating is correlated with salary (skills)
2) A+ > A > A- as salary/player skills. A+ might not be the best everytime because too high RB or JS can boost player's salary. I look for PF > PG > SG > SF > C. SF's can have high JS and RB but they may lack a lot of other skills and still be high salary. C's probably doesn't have secondary skills.
That salary table is not correct right now, because BB's have changed salary formulas a lot since. They are a lot less.