10 things that were in TR (or POM) and 1 that is.

Vera was named Jessie. Her name was ultimately changed because now Jessie is a relatively common name with connotations I did not want to keep.
There was a king. He was Joshua, and ultimately useless.
Karrie was two characters, Persee and Karrie, and Persee served no ultimate purpose so the two characters became one.
Twin Reflections was called The Palace of Mirrors, which wasn’t really applicable except for way back when.
Karima (who served Karrie’s basic purpose) was a part of a triplet set. Charna was her other triplet (thought to be twin), who was like Dalena, and a servant named Mucio who made some poison with smoke and amber? This was back when I used Google Translate for Latin so I could be Latin-y.
Everyone had armbands that revealed their intentions. In the first draft of first drafts, it was explicitly clear Vera, then Jessie, and Mark were the children of Missena (then Misseva) and Joshua, because they had armbands! Each had a term in Latin explaining a character trait (Misseva had fidelius/faithful which was really not good), and Jessie had something regalis (royal blood) while Mark had noble blood? Again, fifth grade me was a tiny being who tried.
Vera and Mark were very fraternal twins who were not brown. Jessie was pale, turquoise-eyed (because she’s special, okay?), and had straight black hair. Mark was brown-eyed and had brown curly hair, mixing the traits of Joshua and Misseva.
The “book” ended with the reunited family staring into the sunset. No joke.
The sequel (Key of Secrets, which very few have read and which no one should ever read ever), featured Leina (then Leyna, which I changed because of Heroes of Olympus ship names) as the avatar. I was easily influenced.
Jessie and David were love interests and so were Mark and Leyna. No further comment.

1. The maze IS sentient. That is all I have to say on that.