Celestial Lite vs. Pro Versions

What is the difference between Celestial Lite and the Pro version? If the Pro version would save us development time or provide other features, I would like to know what those are so that we can upgrade if it makes sense.

Also, if we develop in Celestial (Child) and want to switch to Encounters, would the custom changes we make in Celestial be easily transferrable to Encounters?

Thank you.