I would use both coaches. One that is fun for a few years and then the serious one when he gets older. It is important to have fun when you are young. As you get older most kids want to play well and be competitive.
Where do you live? in the next 6 months, there should be several days that are playable..... unless you live up north
2 years ago in Maryland, we were playing on Christmas eve.
coordination is decent, he gets the proper position on the backhand. And we tried a two-handed forehand that worked, however, he is reluctant to stay with that option.
There is at the High School level. I had a boy who hit 119 mph and rarely won his serve. His first serve % was less than 20, his second serve was about 30 mph.