Considering a trebuchet is gravity based, a counterweight wouldn't weight anything and it would actually just sit there doing nothing. But you'd be right about the orbit if it was launched from a planet with zero atmosphere.
The docking ring made sense to me, but I never understood the logic behind the upper pylons when they had the landing pads.. and any large ships would immediately block access to the other pylons. What was the goal, to put ships within proximity of one another while constraining degrees of freedom? Surely facing them outward would've significantly improved access and made chance of collisions infinitely less likely? Then they draw these diagrams showing cutaways and it seems like there aren't enough windows compared to what you see inside on the show. arg