Pretty concerned about those long weak stretchy springs being out by/under your feet or missing altogether. Strong believer in springs at both ends of brakes and throttles. Throttle spring on engine will pull the throttle closed as long as the distance and restrictive curves in the cable and drag of rods and the weight of the pedal don't interfere with the recoil, but you really should have that return spring on the pedal. Yours looks like a disaster waiting to happen.
There isn't a return spring for the brake at the pedal at all that I can see, not one at the band that I can see either. Lots of spring assortments out there for just a few bucks, but I recommend you get one that doesn't have 95% waste for the project being done at the time, like a gokart. Here's one of many that seems to have the heavier springs called for in a heavy mechanical movement like cables and rods...................
Amazon.com: Swordfish 30370-152pc Extension and Compression Spring Assortment : Industrial & Scientific
BTW: That's the right collars, quick change without R&R any parts, no setscrew dings in the axle, etc.