Can I put a reminder on a checklist item?

Yes. A reminder hangs off a due date, so the item needs a date first.

1. Open the item.
2. Tap the calendar icon to give it a date, and the clock icon to give it a time.
3. Turn on Remind me.
4. Choose how far ahead you want warning.

You can be reminded at the time itself, or 10 minutes, 30 minutes, an hour, a day, two days or a week before.

Reminders live on checklists. A jot has nothing to be late for, which is why the option is not there.