Username change anytime we want

That could be abused :/
Yes, but only on april fools day imo

Why would you even want to change it that often?

If people change their user for halloween, trolls will steal their username

Wrong, for the entire thirty days nobody is able to steal your username because you're technically still using it on your account for your "previous username"

I have decided that I will only change my name for Halloween and Christmas from now on. This will be my third year changing my name for the holidays.

I never ever pay any attention to them as they don't mean anything to me.
Tho I am a troll myself
I'm pretty sure they don't get to you.
Hopefully?

Oui