Hi Mark!
This is a small mod to Saq’s autolist plugin that makes it effective for the check list input format. This is the mod: https://talk.tiddlywiki.org/t/tw5-re-editor-auto-list-how-to-add-to-and/1102
In my workflow (beyond the Autolist mod mentioned above), I have fixed a minor functionality issue in tw5-checklist itself, and I added an option in the configuration tiddler to hide/show the input form. Together with a toolbar button/keyboard shortcut, the checklists behave like numbered or bulleted lists during input.