Is the R7000 good enough for 200/12, possibly more?

I have right now 200/20 (telenet cable in Belgium). The R7000 is giving me full speed on my Xperia Z2 tablet, over 5GHz, at least according to speedtest.net, so I'd say you'll be well served with it with your current connection. On the tests that I did with iperf I managed to get close to the theoretical speeds on 2.4GHz and 5GHz, so it should also handle your future speeds. Of course, it will depend on the size of your house, wall materials, neighbouring WiFi, etc.

As for the firmware, I was running the v1.0.6.28 beta for some time, and am now on the 1.0.6.54. If you don't have any arlo cameras, I'd recommend you to stay with 1.0.5 for now, as you won't gain much with the beta.