Hi...Congratulations! You will likely find that Bentley will become very special to you, if not already...they are a great breed!
The silky coats are shiny...cotton coats are not. How often Bentley should see a groomer for trims depends on how you maintain him yourself and how long you want his coat to grow, but generally 4-6 weeks, however, he should be combed/brushed daily with all tangles and mats removed and a bath at least once a week or so.
The "best" dog food is one which is nutritious and meets his needs, and is as chemically clean as possible...that Bentley will eat.
The particular brand is a matter for you to choose...brands are always a subject of debate since one dog will do well on one food while another will not, etc. I advise...read labels...research ingredients...research products...research manufacturers...until you find "the" one you and Bentley like.
All puppies will play 'bite' but they should have learned "bite inhibition" from their dam and siblings since Yorkie puppies usually stay with them until 12 weeks old minimum. You can tell him "no" and withdraw the bitten hand, make a "zuzshing" pain sound, etc. to help him learn that biting hard is not acceptable, but do understand he will be teething and will bite and chew and those sharp little teeth may hurt or even break the skin. I do not play with bare hands with puppies and kittens until bite inhibition is well established choosing instead string toys, or keeping my hands out of their mouths, etc. My Yorkies are 2 yrs old and I have been been letting them play bite my hands since I got them at 14 mos. and 17 mos. old but they were all done teething.
Again, congratulations. I think you are just going to love having Bentley so much!