I'm sorry, but the war was against whom, and which is most common? Feels like two sentences would be clearer.
The war was against Shade, aka the Netherese Empire.
And Waocks and Tieflings are more common now.
There are new races like Dragonborn, Shifters, and so on.
Shadar Kai are now elves now instead of an offshoot of humans.
Over a hundred years of history has happened since 3e.
A new Queen, new Nobles, the Brimstone Angels, and so on has happened, Swordmages (Eldrich Knights in 5e) are a thing.
New Gods have appeared and olds ones returned from the dead and almost all the Demigods went from being demoted to Exarchs in 4e to being promoted over demigods to to Lesser Gods.
New kinds of Warlocks and other strange magivs have appeared including a lot of at will magic, a form of magic that only existed in like the rare Binders and Warlocks in 3.5e.
An Eventual called the Great Rain occurred, nearly drowning the nations of the Sea of Fallen Stars, and caused a whole bunch of people to become Storm Sorcerers, and ended with a magically enhanced harvest.
Their is more land then there was in 3.5e, alot more, the Sundering made the Faerun bigger, things have gotten further apart.
Various demon lords have run amok, Dragons, and Giants have run amok.
Resurrection spells can't be relied upon anymore, at least not until after ToA thanks a Greyhawk Liche named Ackrak.
The greater geopolitical is radically different.
Heck even Abier Toril means something different now, they added an entire twin planet because Toril wasn't big enough and the two wolrlds have a habit of swapping locations like twin sisters swap clothes.
Cormyr is mirrored in the Feywild, Shadowfell, Border Ethereal, and various border Elemental Planes. The Elemental Chaos is a thing.
I could continue, this is why when WotC suggests using the 3.5e FRCG to new players of 5e I cringe, it's useful as a historical document at best, 5e plays to nostoligia, but it's still it's own beast as it's been shaped by every single edition and it has it's own stuff going on on top of that.