Gary had some reservations about the shift linkage. So now it's my turn to be a somewhat grumpy old man again.
That brake linkage is just as bad from an engineering and safety perspective. The linkage rod is in compression, which also makes it prone to buckling, being long and slender. Any long, slender rods should be in tension, like the original brake stays. The system should have enough strength to take at least 200lbs pedal force. That means at least half a ton on that rod....
And if that brake arm drags in a right hand corner, the rear wheel may lock up.......
Not wanting to be too rude, but in its current state, that bike needs training wheels to prevent bad things from happening.