Multiple characters, one account, two systems - help?

Apologies if this has been addressed elsewhere - I did try searching but could not find an answer anywhere.

Basically, I have my one single S-E account, and on there I have my character (Cerberus) and my wife has her character (Moogle).

Now, we currently play on PS3 but at the end of this month I'm also buying the PS4 version (because I'm a collector), which will mean that I don't need to upgrade, and we can play on either PS3 or PS4.

My burning question is... given it's just the one S-E account, will I be able to play on one machine, and the wife on the other, at the same time?

Another question is, if I pay for her to transfer to Cerberus, will we both be able to sign in to my account and play together using our own characters?

Chances are the answer is blindingly obvious, but I had a very late night last night, it's very early now, and I'm soooooo tired. :D

Many thanks in advance!

No, in order for you to be logged into the game at the same time you both need to have separate SE accounts tied to separate PSN accounts, have purchased the game for both accounts and have two subscriptions for each. There is no way to transfer a character to a different SE account. This is standard for MMOs. If you are planning on rebuying the game and want to play together probably your best option is to tie that version of the game to a new SE account and its own PSN account and one of you starts a new character.

Well, that wasn't the answer I was looking for, but thanks for all the same. At least I know now, and knowing is half the battle, etc. :)