When copying top athletes, it is very important to understand the elements that make a champion successful.  For example, Ma Long is the 2015 World champion BECAUSE OF his fast footwork and other strong aspects of his game.  Fang Bo is better than many top players BECAUSE OF his powerful forehand.  Zhang Jike won the last Olympics BECAUSE OF his strong mental game.  These are some of the elements that make champions great.
 
Now, there are some habits that you should NOT copy.  For example, one of my friends (rated 2700) didn’t have time to eat a proper breakfast.  He grabbed a donut, walked out onto the court and played amazing!  Should you skip a proper breakfast and just eat donuts on tournament days?  Of course not!  This particular player was amazing IN SPITE OF his diet NOT because of his diet.  What about Thomas Keinath’s forehand?  (Thomas has a very strange forehand) Is that something that you should copy?  He won the US Open 3x and has a 2800 rated IN SPITE OF his technique, not because of his technique.  What about smokers?  Many elite European players are smoking between practice sessions and right before tournament matches.  Again, they are good IN SPITE OF their smoking.  If they didn’t smoke, had better rest, had better technique, had better attitudes, had better nutrition, had better outlooks on life, had better training, and had better coaching, then they could possibly even reach a higher level!
 
I recommend that you choose 1-2 elite players to copy.  However, you need to continue to evaluate and re-evaluate, “Is this player good BECAUSE OF this or is this player good IN SPITE OF this?”