Questions regarding Heavensward PS4 Upgrade

Hello! New to upgrading and I have a few concerns. I hope I'm posting this in the right place.

1) Fairly certain I know the answer to this one since it is an expansion, but for peace of mind, I originally only had A Realm Reborn on PS3, but will be getting Heavensward for PS4. Since I don't have ARR on PS4, would I be unable to launch the game at all regardless of ARR being tied to my service account?

2) When getting Heavensward, I know some people had issues where their copy of the game (or their upgrade of ARR) would actually be assigned to a new service account (as in a new service account would be created), sometimes due to strange wording when upgrading. Is there anything I should know that I should avoid before upgrading, or anything of that sort?

Thanks!

I dont have an answer, but I started with the PS3 version and upgraded, and then when I logged in and activated heavensward it sent all my preorder items to a side character I never use without giving me option to change it. I wonder if it has something to do with the fact that that lvl 1 side character was made after upgrading while my primary was from the ps3 version. I'm very frustrated and can not get in touch with SE to help. I recommend waiting.