Jokes aside, the three characters from TPM that would “break the Internet” are QGJ, Jar Jar and Maul. Referencing TPM and not the entire PT makes it seem like those characters were featured more in that film.
That hooded character in the 1st trailer still has me puzzled. Based on Maul’s current Rebels storyline, I could see him actually making it to the DS but being that big a part of the story would take over the narrative.
As far as Leia and the droids, I could see the droids being with Bail on Yavin midway through film and he sends them to meet with Leia, who we see on transmission at the end. Anything more from her would be distracting, in my opinion.