The moment they kissed and declaring boyfriend and girlfriend.

It should be put here instead of the hug scene

He is a seed holder and he lost himself.... So yeah he is a villan beast since he kinda lost reason

No that's another one if we go with novel lore

There should another seed of darkness holder who has lost his mind and that should be him and helmut would fight him although it would be happen later at the next arc... Or 2 depends really on the person.

She went back living in the temple

Well my memory is a bit hazy since last read like a year ago

Diana would try talking to kael again win him over and so

She does not succee ofc.
((After that the rest of the story)))
Hestia would collect the coraption of the temple.

Hes and some nobles would carry a complain or something to the court.

Crown prince blackmail hes to not get involved in it tho i remember it's about the duke title but idr

Nobles did tho 

Diana still have the mind set until the end

Diana and crown prince divorced 

I think hes become pregnant at that time.

Crown prince found new wife

Emperor made him by his side since he pited her until his death 

Kael and hes 1st son but don't remember if he saw him or not i think he saw

After emperor dies she went back to temple and lived quietly tho with the same mind 
After some years they had 3 children and at the last paragraph of 2 she was pregnant with the 4th