The aperture is not in Blender but is available in the exporter
The place where you control it depends on the version you use (main panel for v0.9x, camera panel for v1.xx), but you can animate it (I can't retrieve a sample scene I posted, with camera tracking, DoF tracking and aperture anim - it's probably somewhere in the middle of hundreds of posts).
For the DoF stuff, if you don't change the default values from blender the autofocus of Octane will be used. Otherwise, the focal point will be driven by blender's setting, with either a distance or an object to track.
I'm not a CG specialist and may not always use the proper terminology, but to my understanding what you want to achieve can be done with the exporter in its actual status (don't forget it adds options not present in blender).
[EDIT] here's the link I was looking for:
download/file.php?id=7933 . I can't remember if aperture is animated in this one but it can definitely be.