The Facebook poll is the only data point we have that is actually recorded, and I don't think it's the end-all-be-all, but your wording makes it seem like you may have slightly misinterpreted what I said. I was saying that, if their importance order was like they said in the answer, being:
1. Unique Weapon Styles
2. Story Relevance
3. Popularity
Then Setsuka and Hilde would have made it in instead of Amy and Cassandra, by point number 1.
In reality, their actual process would seem to be:
1. Story Relevance
2. Popularity
3. Unique Weapon Styles
Because Amy has the most story relevance of all the missing persons, due to the big push she received from Raphael's Soul Chronicle, and will be receiving in her own Soul Chronicle, due to Azwel's apparent involvement with her and Viola, after his involvement with Raphael was already established. Cassandra, on the other hand, is getting in by means of popularity, because her story relevance in this block of time is not very high (that is, assuming they stay with "before SoulCalibur II" for the framing, which Amy's Soul Chronicle does not actually appear to be doing, but that remains to be seen), but she's definitely popular and highly requested. But neither Amy nor Cassandra fit the bill for unique weapon styles, allegedly their most important factor.