In NUE:
This map shows where you catch the bus in NUE - the stop is at the side of the Movenpick hotel: https://www.lufthansa.com/content/da...rg-airport.pdf

There is no need to go to the check-in desk, just be waiting at the bus stop 15 minutes before departure. You should check-in online and show the driver your boarding pass - they just need your name to check off against his list.

In MUC:
There are check-in machines within 20m of where the bus drops you off, and you check in your luggage here. 1 hour 20 minutes should be enough, especially as in my experience the bus tends to arrive early.

Other points:
- I have no experience with the child seats, but the website seems to indicate you need to bring them with you: https://www.lufthansa.com/de/de/beso...ingungen-bus#6
- when the service started it was an executive coach with just 3 big leather seats in a row and power plugs etc. Last time it was just a normal coach.
- as far as I have been able to tell you take whatever seat you want. The seat number on the boarding card hasn't matched the seat numbers on the bus.