Good points, but Passengers does have two of the biggest draws in Hollywood atm in Chris Pratt and J-Law, and Rogue One has "Star Wars" in the title, and in a post-Force Awakens world, that's saying something. While those movies don't directly target the family audiences the way Sing does, they certainly will have their attention captured more strongly.
I would agree w/you, if it weren't for the fact that Illumination are absolute geniuses of marketing. The first teaser for Pets took the Internet by storm, currently at 13+ million views on YT (pretty much the same amount as KFP 3's first trailer which dropped at around the same time), and theatrically, it was released, w/a year in advance, in front of Minions - which means it was exposed to at least 1.1 billion people (well, less than that cause many of those are folks on repeat viewings, but whatever) - and I've heard from friends that, when they went to see it, the Pets trailer got a bigger laugh out of the whole audience than the movie itself. The next trailer should drop around January alongside KFP 3, and again, beyond that, it's all down on how clever they can be in their advertisement. Not to mention they have the presence of some pretty big comedians like Kevin Hart and Louis CK in it. It won't be as big as Dory or KFP or IA5 WW (domestically I can see it beating IA5 tho since IA movies were never big US domestic hits), but 700+ million is the bar it has to reach imho.
Sing will just benefit from the post-Pets brand goodwill effect, as well as the added all-star voice cast, and even tho it will not make as much as Pets, it'll still be a big hit w/strong 2017 legs in it.