First of all, how to get "free" access to the courses on Pluralsight.com?
Easy, go to the Visual Studio Dev Essentials, join for free and then get the 3-month subscription of the Pluralsight.com.
What Unity courses sound useful and interesting?
Level 1 Let us ramp up with the Unity. The 2 courses below seem legit. Their total duration is like 6 hours, just watching and learning without practice.
Beginner's Guide to Unity (Duration: 1h37m)
Introduction to Game Development with Unity (Duration: 4h31m)
Level 2 Some practical stuff that could be helpful to port current games talking to NodeJS server based on Cocos2D-X. Their total duration is like 7.5 hours without practice time. The actual porting is the practice if these stuff are right to learn.
Explore 2D features in Unity (Duration: 2h19m)
Unity Multiplayer Game Development with Node (Duration: 5h17m)
Level 3 Some advanced Unity thing that could be helpful in next steps, VR & Unity 5! They are optional for porting your games of course. But who knows what would happen in future.