I've made some adjustments. The hamburger menus now slide in from the left, echoing where the sidebars are on wider pages. The group hamburger menu now has all the same items as the full screen sidebar, in the same order, and with the Admin toggle. The user hamburger menu (/groups, etc) now has the missing Topics items.
Question: The group hamburger menu duplicates the items that appear on the bottom menu (Messages, Post, Chats). Should I remove those items from the hamburger menu?
Please let me know if you have any questions or suggestions.