A committee of the powerful Constitution Revision Commission advanced several constitutional amendments that may appear on voters’ ballots in November, including a proposal that would make Miami-Dade’s sheriff an elected position and an ethics measure that would bar former officials from lobbying for six years. In a three-hour meeting, the commission’s Style and Drafting Committee approved its plan to group 24 constitutional proposals into a dozen amendments and send them to the full 37-member commission, which has the power to put measures directly before voters once every 20 years.