1. Inform KCC. Make sure they acknowledge your request. Make sure your DS260 shows your home country home address, and if it doesn’t unlock it and change it.
2. Depends how busy they are, but unless you have a particularly low CN it doesn’t make much difference if they take a few weeks?. Yes, my CN is high
3. Yes, it’s a different type of 2NL. Yes, you will have to pay the fee again, this time at the embassy when you go for interview,
4. It would be advisable to show you’ve maintained status if asked so that the embassy knows you are not subject to an entry ban period.
5. Your L2 visa will probably be canceled without prejudice when you get your DV visa. You can only enter on one status.
6. You appear to misunderstand the process. As soon as you enter the US on an immigrant visa you become a LPR and the visa stamp becomes a temporary green card valid for one year. You can work immediately on that basis, you don’t need to wait for a plastic green card. Usually the only hold up is the wait for a SSN, but you presumably have one already. Yes, I have the SSN. it's great to hear that I can resume my work with my employer without any wait.