Ollivander cause he has the greatest widom amongst these, and also doesn't disregard "true" facts

@Hazard18 Acceptable but we can't say that he has the greatest wisdom, what about the dueling champion Filius Flitwick and also it can also be the Lovegood cause they have been in Ravenclaw for many generation like the Gaunts in Slytherin...But I'm not saying like Ollivander cannot be the heir but there are chances he may and may not...

^I think ollivander will have the highest chance, though Flitwick is also a good candidate

Honestly, I think Hermione! My headcanon is that either Rowena had second child (or Helena had a child) who was a squib and left for the muggle world, that person eventually became the ancestor of Hermione. But out of the ones here, Luna.