Funnily, I have been that guy at the last 3 places I've worked at. Every place has some amount of cruft code, and I love sniffing it out and deleting it.
Uhh. No. That's a common misconception held by people that don't actually read their T&Cs. Your worth authorization is tied to "a" employer for the first two years. The employee is completely free to quit and enter into a contract with another employer. All you have to do is go get the name of the employer updated. It's just a formality and nothing else.
Yes, you have three months to find a new job if you're fired, but it's Europe, you most likely got at least a 3 month notice as well.