Is all dis really needed if i use unity

Answer 1

If you use Unity, you'll be needing quite an amount more than all this.

Answer 2

Eh, if you know C# really well that is all you really need.
Monobehaviour is easy enough to figure out without knowing anything about it (IMO (and self experience)).
Again, that would be if you understand C# really well.

Although, I'm excluding things like Unity's interface, and components (Cameras, Physics, Rigidbodies, NavComponents, sprites etc..), animations, files (Resources), etc..
Those are things you can't really learn well without trying unity though.