Ulti knew about SeeD. The only way she could have known about SeeD had she come from the past, would be if she was there when the idea was formed.
Not IF she is already possessed by someone from the future who knows Seed.
(Note that I said IF which means there were other possibilities which invalidate the argument.I am not backing up theories with theories).

Ok, in the flashbacks to Edea's house, during the time when it is an orphanage, it is a complete, nicely built building. In the "present", it is a broken down wreck.
I had already noted that.That is the best argument someone ever used to prove Ulti from the future.
But we donīt see Edeaīs house on the "future" after all.
We see something difficult to define.Itīs creepy.Looks like the body of a monster.
We see also the White Seed ship and some pillar ruins.