I enjoyed your post and found it quite interesting. I actually started to assess my own lesson attempts. I have been a Kindy Kidz (Sunday School) teacher for 3-5yr olds for the past 4yrs and a crèche (0-5yrs) co-ordinator for 7yrs before that. Though we generally only had the one bible story, our lesson was longer on average 1hr and we didn’t have parents sitting in. We did though also include singing, play/acting the story, craft, games, memory verse and activities (playdough, etc).
This age group is such an important one to focus on, as my Nanny School teacher always said “that in the first 5yrs of life you learn all the skills needed to become an adult.”