Over lunch I had a bit more time to think the situation over that you had laid out in your original post.
If I were an independent journalist going to quite an extend to protect my privacy I would see if it were possible using alternatives to the big tracking networks like the Meta products you’ve mentioned.
If that’s not possible I’d definitely avoid using their own proprietary apps, and use open source alternatives for Facebook and Instagram instead, or a (TOR) browser with container tabs.
I would probably keep WiFi disabled and use mobile data with a VPN or TOR, no hassle with MAC addresses then either, just your ISP that can triangulate your position.
Having thought more on it, I’d say using the Android layer with a form of spoofing or Waydroid perhaps with multiple containers or spoofing should cover your points 4 and 5 as well.
If you get that deep into it, I’m not sure any regular hardware or software is going to cut it anymore either, I’d probably want open source hardware with kill switches per function such as the PinePhone Pro, which might even work with SFOS and has replaceable batteries which are separately rechargeable.
Always fascinating thinking of the options, though I’m glad I’m not depending on them. Good luck with your search, hopefully this helped! 