I have tested the ACES output from Blender and it works well in Natron as described (even using my custom OCIO config including my monitor profile).
However, as mentioned, the OCIODisplay node is required right before the Viewer, which brings a usability drawback:
After that it is no longer possible to use “1” key and others to quickly connect any node to the viewer for a quick debugging. It will avoid the OCIODisplay node and the display is not useful.
The hidden-node approach as illustrated by @El_Artista would be really useful. Also, I wonder that the Write Node contains the OCIO color transformation settings, so it doesn’t need the OCIODisplay node. The Viewer node has no such settings tab/page, so I guess adding that would be another way. Or perhaps make a setting for “1” key to connect to a specific node instead of just Viewer 
Edit: Now it seems that the conversion in the Writer node is doing something else, so I have to add OCIODisplay node before that as well. It is not an issue there though.