I was wrong.
Here you can see the normal grip in third-person. Looks pretty decent... until you walk, in which case the crossguard clips through the hand.
Here's the normal grip in first-person. Same mesh, completely different position. For some reason, I am now holding the blade. You can't really see it here, but it's noticeable in-game.
And here's the real baffler...
Blocking. I just... why? Why does the hand suddenly shift all the way down near the pommel?! It makes no freaking sense!
So yeah, no two-handed swords using these animations. It's just too inconsistent for it to look convincing in the slightest.
Baseball bat animations work much better, but the way the player character grips the sword looks far too rigid for historical accuracy... but oh well.