Rita didn't yet know about Rick's latest moves, but even without that knowledge, she would never underestimate him.
She truly intended to help the Jones family as she promised. After all, why not make some money? It was just a middleman job, after all.
After gouging out Aaron's eyes, their past grudges were settled. Rita had no habit of exterminating entire families—her main enemies were always Rick, Zoey, Sanchez, Camila Taylor, Henry Taylor, and the Lopez, White, and Taylor families, as well as anyone who had wronged her.
Thinking about it, she realized her list of enemies was getting pretty long, almost like reciting a menu.
But she didn't plan on harming the Jones family further. Her philosophy was simple: return grievance for grievance, revenge for revenge. While she wouldn't let Rick and the others die easily, she'd only make the lives of those who didn't deserve death miserable.