First, thanks and credit to the nice designs here.  The #4 ornament reminded me of a pineapple, so I scaled it to create a stouter look and designed some leaves that can hold an attachment mechanism.

The ornament base should be printed in vase mode and the leaf top should be printed normally.  Afterwards, use a piece of string or wire (I used wire) to create a loop at the center of the the leaves, pushing it through to the bottom of the topper, and then tie or twist at the wire/string to prevent the loop from being pulled through.  Then, using a bit of cyanoacrylate glue, secure the top to the ornament base.  I've designed the topper to not fit too snugly, but will hold nicely with glue.  Once set, use string, ornament hook, monofilament, or whatever your preferred method is for hanging, to secure to the loop you've created at the center of the leaves. 

The photos show the final product printed with silk PLA (gold for the base, and jade green for the leaves).