A fork will result in chain split (and a new coin) only if miners keep mining the old chain, without the new features (like ETC), and that's not the case.

So we will unlikely have a new coin in both cases.

And beside that there is something implemented on ethereum called "Ice Age" (https://www.coinstaker.com/ethereum-ice-age/), that is nothing more than an increase in blocktime to force an update. That is another reason why is unlikely that miners keep mining the old chain on both forks.