Is it appropriate to summarise and paraphrase complex reviewer comments before providing my answer?
It’s always better to quote the reviewers’ text directly. That way, there is no ambiguity as to what you’re responding to. (Moreover, many journals expect you to quote directly!) However, there is certainly no requirement that you must proceed step-by-step and quote everything in the reviewers’ responses exactly as presented. If something is mentioned multiple times, you could list the different references together, and provide one response for the group.