I have the April Security patch on my Mz2p. The security patches have been coming along give or take every other month. Which is far better than most other manufacturers seem to be doing.
That said, as long as the security patches keep coming at a regular rate, the actual version of the OS isn't quite that important.
As far as that crowdfunded keyboard, that has nothing at all to do with Motorola/Lenovo. The crowd fund sites even state that you're "investing in the development" of something, and that the "rewards" cannot be guaranteed. They're not a store where you pay and you get something in return.
And I will fully agree with Mario, If you're concerned most with having the most recent OS, the Pixel is the only way to go. If you're ok with being behind on the OS version, but very timely security updates are important, BlackBerry seems to be where it's at (sometimes even getting the security patches a couple days ahead of the Nexus/Pixel lines).