To return to the "" canon "" or not.
Mashima made an open end, but whether one really had to choose between cannon or not.
The answer would be canon considering the end.
For scabies, at the end of tartaros they were not closer than other couples, and if we had not had this detail that they sleep together (cover

), during alvarez we would have asked the question if they are already in a relationship or not.
We know that they spent 1 year together, worked on the council, but what do you do for 1 year they are in couples you do not know, or who is declared in 1 st.
For Gruvia,
If in the end they are not together, it is because Gray is just horrible towards Jubia, he had to give an answer to Jubia at the end of the war, Jubia is sacrificing for him.
Gray must show more consideration for her.
For the jerza /
Jellal has no excuse for not being with erza, he is free, forgiven for his crimes.
He has more than go to see her and ask for her.
For the nalu:
We know and guess that lucy is in love with natsu and what awaits her, but natsu is not a romantic and long to relax and also that in the head of natsu, he must see lucy as his girlfriend but he do not understand the interest of marriage and kiss XD.
The shot of "" we will always be together "" is quite explicit, when we know that lucy is in love with natsu, she wants to get married and have children.
And even they are always together, in a team, on a mission and they sleep together (even if lucy complains because he does not know XD).
So they can remain "" "friend" "but it did not last all their life but it is probably lucy who will do the first step.
Here after everyone is free to think what he wants and if not I wonder if someone will ask him to make the child jerza and laxmira XD.