It's a question I've seen pop up every now and then. If you look at the current distribution landscape in any given enterprise today you'll probably see a standardization on one distribution, with a few exceptions here and there. This is mostly due to the need to have ease of management and the same goes for container OSes. If you mix several of them you're adding on "management tax" for the underlying OSes, even if the containers might be managed by a tool on top of it. Deploying/configuring/managing CoreOS is different than RancherOS which is different than SmartOS, for instance.

I say try a few of them, including the tooling that comes with them, and since the containers look the same and will behave the same on all of them you can easily change your underlying OS (and tooling) in this testing phase. Then try the different tools that can be used on top of them and I'm sure you'll find a mix that works for you :)