For every achievement, make sure you're using the Western All-Stars. Reason being is because you can substitute a wide range of the best players in the West. Now, once you've finished your scoring achievements, turn your scoring sliders down and substitute all your tallest players in. Now constantly steal the ball back from the other team and start shooting the ball from long distances. This will ensure a definite miss and allow your tall players to make the rebounds. This shouldn't take too long.
Note: You can use a second controller for all of these and the achievements are unlocked once you've COMPLETED the game. Please also make sure that auto-subs are off so that the game does not automatically remove players that are currently playing.