I'm usually not well up on what the management plans, but this week a whistleblown insider informed me. I'm usually not well up on what the management plans, but this week an insider informed me.

A "whistleblower" is someone within an organisation who reveals its illegal activity.

After I boughtbuying a full set of new clothes, I am now'm skint.! After buying a full set of new clothes, I'm skint!

Your sentence is correct, but the wording was a little unnatural for such a colloquial word.

I was super chuffed when I learned that my neighbours will move to a new home – I did not get along with them at all. I was chuffed when I learned that my neighbours will move to a new home – I did not get along with them at all.

I don't think the intensifier "super" is necessary here, since "chuffed" is already a strong adjective. Super doesn't quite sound natural with it.