The one that appears to be connected at the front has another beam that goes down to the other wheel knuckle. The one at the front is connected to the servo for the steering input. Hope that helps! Look up “dual swingset steering” for more information.
Time will tell! I’ve made another person’s design for an RC buggy out of PLA and it has held up fairly well for the most part. Worst case I can try PETG if I have issues.