New approach. I needed to remember that this first unit is skill-based. Students are not "discovering" this content (although it was supposed to be review), so I did deviate more than I would have liked and demo the skills required to solve systems of equations graphically and algebraically. I still did so in a very socratic way - I had students guide the class through graphing the lines as well as the steps needed to manipulate equations for substitution.
Overall, the lesson was extremely successful and kids seemed more positive about their abilities.
It's possible I tried to implement too much too quickly, especially will skill-related content that students weren't entirely comfortable with. I have no plans to abandon my plans, but I'm ok with adjustments as long as the class remains student-centered.