I'd say the Eliza commentary here only really applies to her post-CCC writing, where it makes sense for her to be different because she goes through some quite big changes due to her relationship with Hakuno. In CCC, while she could be replaced by any other noblewoman kid who killed commoners if it weren't for the claustrophobia scenes, there was a relatively decent distribution between researched content and original content. More so than most of the F/sN cast imo.
As for the Nightingale commentary, I honestly have no idea what you're talking about. Nightingale always had a huge reputation as a severe woman who wouldn't take a no for an answer and her life achievements include:
-defying her expected social role as rich lady to work a job usually performed by fired maids, widows and prostitutes who grew too old to get clients at the time
-cutting ties with her family over then still using their money to improve hospitals and buy uniforms to the soldiers
-pretty much saying "you're wrong and I'm right" to the entire medical system of her time
-working her team so hard that she made 22 nurses quit their jobs mid-war
-ignoring authority and bureaucracy, and even going as far as lying about the Queen's orders to get reforms done and equipment delivered sooner
-continuing her work after war against medical recomendation
Even without the Mad Enhancement excuse, I honestly still can't see any other character more "accurate" for Florence Nightingale than a self-destructive unstoppable workaholic who thinks her own opinions and priorities are the only objectively correct ones. The only thing I really feel the F/GO interpretation for her is lacking is her religious side, since she wrote whole books about theology and only became a nurse to begin with because she "heard the voice of God" ala Jeanne D'Arc.