>>40047037>its safe to assume its the same one and this is happened after they'd met it before before its death.
Ehm no? The Eon Movie was a gen 3 movie, while the Latios of Tobias was in a Gen 4 Anime, so it's something happened after.
Of Arceus as we know there might be only one, as Dialga, Palkia and Giratina, but this is because they are literally gods, and for that can exist only 1 per universe. Indeed Arceus in the event of Sinjoh had to create a whole new universe for giving you one of the newborn legendaries.
Mewtwo can exist more than one, because it's a human experiment.
Even the regis can be more than one.