Only sales from within the past 3 months are valid for suggesting (the past 2 months when sales are common). That means your second and third sales aren't relevant here.

Your first sale is actually this: https://backpack.tf/profiles/76561198296168912#!/compare/1486684800/1486771200 - Sold for Blizzardy Chieftain and 1 key pure. If you check the item histories you can see that the names and id#s match for these two hats, which is how you confirm the sale. Not every item in each compare link is part of the same trade, you have to find the items grouped together that have matching histories in order to determine what sold for what. However, the Chieftain's price is outdated (any price older than 4 months old is considered outdated), and would need a mini-suggestion in order to be usable. Unfortunately, I'm just getting 504 errors from bp.tf right now, and it won't be possible to find a sale to use as a mini-suggestion until that stops.

Another Waxy sale I found: http://backpack.tf/profiles/76561198155066949#!/compare/1486512000/1486598400 - Sold for 14 keys pure

The other problem with both of these sales is that they're nearly outdated as well, but I wasn't able to find any other usable sales here when I checked, so that's all there is right now. The amount of sellers for 16 keys does suggest that a drop is needed, but your range would need to either include 16 or be below it in order to be valid.

Hope all of this helps somewhat.