My daughter also noticed as another poster commented that they left out the baptism scene where Eustace as a dragon scratches off his scales and then backs into the ocean, sinks and then emerges from the water as a boy. She said it would not have added much time to keep that scene as it was written.
I never thought of it as overtly religious. I think with eustace saying “I could not do it myself” he accoplish the same end. (only through me ...)
“it hurt but a good hurt like a thorn being pulling. or words to that effect)