Setting up Soundbar with Headphones

[NMS]

Disclaimer: I'm an audio noob.

 

I recieved yesterday a LG SJ5 soundbar. And I'm wondering whether I could connect it to my PC along with my current headphones (Corsair HS30 Raptor).

 

The soundbar has an "Optical In" port which I assume I would use with the "S/PDIF" port on my motherboard (Gigabyte B350). 

My current headphones I use as main speakers (Line Out) and microphone (Mic In) through an included splitter.

 

So the questions are:

1. Can I use all 3 ports (Mic In, Line Out, and S/PDIF) for soundbard and headphones at the same time and simply switch between devices in sound (device) settings?

2. If not, do I require a DAC? And which one would be suitable for my setup?

I'd prefer the DAC to have some sort of physical control over which output device I want to use (soundbar or headphones).

[MCManiac52]

That should work fine yeah, if you're running windows 10, check out ear trumpet in the Microsoft store, it's really nice for switching between audio devices.