Emojis sexually reproduce. It must be exceedingly difficult for certain Emojis to have sex, especially the ones representing apathy and sadness.
We're spared any implication that Emoji reproduction works the same way as human reproduction. Whether this is better or worse depends on your imagination, making this less Nothing Is Scarier and more Nothing Is Squickier.
Every time that you take that old phone to get recycled or break it, you are committing mass murder against the sentient workers inside each of the apps. At least in this universe.
Gene had the ability to express any emotion, and yet of all the terrible things that happened to him along the journey, he only became unemotional when his crush rejected him. This suggests that he felt entitled to have her and placed way too much emotional weight on getting the girl.
Also, anyone whose had an iPhone before can tell you that there is a million ways for one to lose its functions; most usually last only a good few years before the battery life starts to deteriorate, many people shatter the screens or drop the phones in the toilet, and some simply throw away their old phones in favor of newer ones even if the old phone isn't broken at all. In other words, Gene's efforts didn't save Textopolis, it merely pushed back their inevitable fate.
Also, assuming that a user, like Alex, doesn't have the phone destroyed, but merely reset, that means that one phone can have multiple civilizations exist in its lifespan, with one being annihilated to make room for the new one. How many Textopolises have existed on Alex's phone alone that were never able to save themselves?
Notably, the movie didn't end with Gene and the others fighting against this oppressive system; instead, it ends with Gene merely appeasing Alex in an unexpected way, sparing them until the next time the phone glitches. The Emojis merely see it as an inevitable aspect of their existences and something that cannot be fought against. Humans Are Cthulhu, indeed.
The only situation that should require the Emojis to have the face they represent would be when they're used - and they're given a heads up before they're used. Outside of that, there's literally no reason why they should stay with the face they represent.
Alex is too nervous to talk to Addie...yet he already has her cell phone number, which he would've only gotten had he talked to her.
Though it's possible someone else passed her number onto him. Or his inability to talk to her was a more recent development, and he got her number before his attraction-induced nervousness set in.