Dual Threat vs Universal Coverage vs Reinforcement

That's mostly correct. But there's two parts to KO abilities the better reactions when the ball is in the air and the knockouts when the defender contacts a receiver. UC grants both but Reinforcement/Dual Threat only gives the knockouts. UC also contains the one step ahead ability for improved man coverage. But it's also my understanding that adding mid zone KO to a player with Reinforcement (and probably dual threat) essentially give a player all the needed reactions.