Well I'm not reading all of that from those 2 links but I did notice that her original cleric symbol used a longsword. That is the only thing that I saw that even said anything about a LONGSWORD.
Eilistraee uses a Bastard Sword.
Which, is not a weapon class that exists in BG3, but the closest approximation is a Longsword (Which technically, aren't even longswords...)
I also noticed it says "known to use their art while fencing" and fencing definitely does not involve a longsword. It is a rapier or saber (but no sabers in BG3).
Fencing is simply fighting with swords. It's not specific to any type of sword.
The modern day Fencing sport typically uses epees but that is not the only usage of the term "Fencing"
