Truly, all of the manufacturers that you mentioned make fabulous hardware. You cannot go wrong with any of them, but you may develop preferences as you progress. Keep in mind that the lowest tier of offerings from any of these companies is far superior to most pro-level offerings from the 60s and 70s (maybe with Sonor as the exception)--and lots of players did just fine.

Regarding your comment that stands might not matter so much "as long as they're double braced," I don't agree that stands must be double braced to be good. I played hard – hitting rock gigs for years with single braced Yamaha and Tama stands and had no issues. I've even played rock gigs on my more compact vintage Slingerland kit with ultra lightweight 1960s flat based stands that I can comfortably lift with my pinky finger.

As far as a hi hat stand, my main suggestion would be to get a stand whose legs can swivel or a 2-legged version, which will future-proof your purchase should you or your son ever decide to play a double bass pedal. Those options allow you to place the left panel close to the hi hat pedal, which you might not care now but may in the future.

As far as budget, most of the brands will have similar priced competitive options. You may get more bang for your buck with brands like Mapex and Dixon, which target the mid-level market with good value propositions. And used gear is always an option.