How is it Damon tore the dress off Rebekah after the ball, but when she left the next morning after sleeping with him, the dress was intact? Vampire dress?
When the joining spell shows the names of the Originals in runes, they most resemble Saxon Futhorc, given the Mikaelsons' heritage, Norse runes would make more sense. Regardless, instead of "Elijah" in the bottom right it has what is clearly closer to "Mikael" (though it's more like "miuoel"), suggesting a prop designer confused the two names written down in runes.
It is Elijah not Klaus who invites everyone to join the family in a "Centuries old waltz" not a "Thousand year old waltz". Therefore the listed character error is not correct since the 16th century is centuries ago.
Klaus invites the party guests to join the family in a "thousand year old waltz". The waltz only dates back to the 16th Century, not the 11th.