Using a Bullet Journal (BuJo) in Obsidian is a great idea. Thank you for this post. 
I first started my BuJo years ago on paper using a note book. My first migration goes to Microsoft OneNote. It was a great improvement to have a digital search function. The migration to Obsidian was the next important step. Now my BuJo ist part of my Structure Notes from Zettelkasten method. Links between BuJo notes with Permanent Notes are a source of valuable insights.
And the best of all: There is no need for a plugin. It could be done with basic features from Obsidian.
Have a look at my stack of collections:
