Sure,
I've simply connected the Xim Apex via USB to my laptop and then connected a mouse in port 1, keyboard in port 2 and my DS4 controller in port 3.
While in game, I can see the PS4 icons (x to start etc), also, when I pick up my controller (whilst connected to the XIM) - it works fine.
Further - I'm able to seamlessly transition from the XIM k/m to my PC controls (ie I can either use wasd or I can use the track pad on my laptop to move the in game cursor) - literally whilst in game - not sure if this is relevant.
Let me know if you need any further clarification.