I'll probably get flamed, but BMX bikes are relatively simple non complex items, I don't see much value in spending tons more on that for a growing child that may or may not take an interest in the sport.

If he does take an interest, and you are willing to upgrade at that point, I can't see where you are going wrong in this approach. Although, I would argue that Huffy falls solidly in the category of "cheap components and gimmicky items", its just that when dealing with a SS coaster brake, there isn't much better out there until you really delve into specialized hobby status.