So your initial user growth was from people who weren't actually able to contribute to the app?

I'm amazed that Google, particularly being involved with Niantic in the app itself IIRC, don't police trademarks on major brands - there were a tonne of apps that said "Pokemon Go" in the title. I'm sure Niantic would have paid to not have them listed and dragging down the brand before people could even install the genuine app?

In the UK I looked for the app, saw a load of fakers and avoided them but I could see others [children particularly] installing a lot of those apps just trying to find the right thing (instead I installed Ingress to get an idea of how it might all work).

Seems like this sort of inability to find trademarked apps in the app-store makes it look far lower quality over all.

What would have been ideal as a user would be a "get Pokemon Go when available" that would have allowed Niantic to roll it out to my Android device and manage downloads a bit more progressively.

That's why the number of retained active users are more important than pure downloads. If I've downloaded something similar (wallpaper, fake, etc..) by mistake the very next step is to uninstall it immediately.