Well I don't know if they had planned Lost and till what. But Adam/Eddy has planned at least till season 5 of OUAT since past 10 years. So basically they know where their story is going, the character growth and pace of their story. Just the circumstances and all they plan each season but they know the big picture.
Frankly, I am not going to watch OUAT with a wait ki when they will ruin it but I am watching this show as it comes with belief and knowing that it will be beautiful till it lasts. So I know that it will be as beautiful as it is today.
As for AnKi, seriously loons you can HOPE but don't keep expectations. Go to each other knowing you won't get any scenes because that way you won't be disappointed and bitter about not getting...and will be able to keep positive energy.