My two cents on recommendations for the highly assertive... Rephrasing as questions is risky and may come off as passive aggressive criticism which will erode trust. Aiming for balance and avoiding generalization seem like better approaches.

Also, for the non-assertive I recommend making it clear that you actually care because that will help to distinguish you from coworkers that aren't participating due to a lack of interest.

Good point on caring, it's easy to forget and we all need a reminder sometimes.

As for the question-reflex, I'm not suggesting asking a leading question that assumes your idea... more an open curious question that seeks other points of view.