2 - Support of 16 bits editing in Elements.
If you use the ACR raw conversion module which works internally on 16 bits, you can do practically all the edits where having 16 bits bit-depth is meaningful. Then you can open either in 16 bits or 8 bits in the editor. All global edits are available in 16 bits if you want. What must be made in 8 bits is using layers or local adjustment tools, where using 16 bits is not virtually, but in my opinion, practically useless.
Of course, if you don't believe me, Adobe will be glad to suggest you use Lightroom and Photoshop or suscribe to the CC...
Not much difference between version 13 and 11: more filters available in 16 bits.