Upgrading from PS3 to PS4: Heavensward Collectors Edition/pre-order items?

Okay so this weekend I will be upgrading from PS3 to PS4 and I'm having a little trouble finding out what I need to do in regards to the upgrade.
I'm aware I will need to re-purchase the game on PS4 but I'm unsure about whether or not I will need to purchase the same editions as I currently possess.
For example I currently have the standard edition of A Realm Reborn and the Collectors Edition of Heavensward. Will I need to purchase the Collectors Edition of Heavensward for PS4 in order to retain my items or will they carry over even if I get the standard edition? Also what will happen to my pre-order items? Will I get to keep those or will they be lost?
Another thing I was told though I'm unaware if it is true or not: by getting the PS4 version separate rather than by going through the free upgrade that was available before, I retain my ability to play on the PS3 as well as the PS4?
Any advice at all would be greatly appreciated.
Thank you in advance.

Doesn't matter what version of XIV you get for the PS4 cause nothing will change on the account except adding a license to allow you to play on the PS4. All your items and other licenses you have will remain the same.

Thank you very much. Saved me a massive migraine trying to sort it all out last minute before it arrives tomorrow.