Avoid Disney Dark Age, when in the 80's they made live action version of fairytales who were failure(except Tim Burton Beauty and the Beast, that movie is aclassic thank to Burton Gothic style, but was box-office mediocre performance) by bad directing and scripts(musicals only work in cartoon) and put in spirale the finance of disney.
But most Important... Avoid Lucasflims gold age, thanks to Pixar, Lucasarts and the prequel trilogy(who were amazing prequel, explain all now was the rise and fall of the Old Republic and know Anakin Skywaker become Vader but show that was the worse choice ever), Pixar is possible, avoid the prenupcial arrange when lucas manage to dropout her wife only paying a meagre sum, in other negotiation, Pixar would have become Marcia Lucas property. But rhe other two are difficult, Nintendo & Lucasarts alliance made videogames who have average of 90% in metacritic and sold millons of copies and the prequel trilogy was the most waiting movies for one of best selling movie franchise.
and if Lucasfilm gold age is butterfly away the Disney purcharse... how that would affect Sony adquisition of Marvel(and maybe butterfly away that horrible mangaverse, Sony if you want to kill the marvel comics simple don't make more)