Something else I've noticed: both Lucie and Gotou Nao have been published in Dengeki Moeou at different times, under those names. See post #513430 (2003-12) and post #1106380 (2011-02). That makes it much less likely they are the same person.
However, I think I may have discovered why their styles are so similar. Gotou Nao's defunct home page was located at st.sakura.ne.jp/~galaxy/, and his circle appears to have been named Galaxy's Child. post #414878 has the english text "Galaxy's Child Home Page". Even though the source no longer exists, the source field retains the original file path and name: st.sakura.ne.jp/~galaxy/lu046b.jpg
While retagging, I came upon post #792854. After some research, I determined the artist was neither gotou nao nor lucie, but instead a third artist (Moo (umineko)), who also has a similar style to the other two. post #270178 also has Galaxy's Child text, and its source is st.sakura.ne.jp/~galaxy/muumuu003a.jpg
Lucie and Moo must have been junior members of Gotou Nao's circle.