DoF is compatible with Translucent Materials. At this point, I have given you all of the information I can provide to you about Translucent Materials and DoF. It is now just on how you are setting up your materials and your scene to get it to function how you would like.
Setting up a custom depth and rendering this in a different pass and you could be able to fake the effect you are trying to achieve.
Material Expression Reference
DoF
Post Process Materials
Here is most, if not all the documentation you will need to get started with setting up a custom depth within a post process material.
Cheers,