Thanks for the thoughts. One of the first things I look out for is end-to-end encryption. I’m not opposed to using WhatsApp, but they hold onto metadata and share it with Facebook, so I tend to suggest Signal instead. I also appreciate verification and a few other security features that make Signal a better choice. More on that here:
Battle of the Secure Messaging Apps: How Signal Beats WhatsApp
This spring, text messages got a lot more private. In April, the world's most popular messaging service, WhatsApp…
Still, WhatsApp is a pretty decent choice.
Yep, targeted malware is a concern here. Of course, the same is true for all software on a targeted device. Folks dealing with targeted surveillance, as opposed to mass surveillance, might want to get some personal assistance.