EK uses T1 in MUC, *A use T2. So the LH *G lounge access won't help you much as you cannot re-enter airside T2 after checking in with EK in T1. There is the Europe and Atlantic lounge in T1, which can use if you have a diners club or hold a C ticket. Both are now airside. The lounge in T1 C used to be landside.

MUC has nice restaurants and bars all over the terminal, with the best selection landside in T2. There are public showers in the Z area which are neat and clean. You can use the SEN lounge in T2 for showering too if you have a enough time.

If you are in EK C you should be fine for the 6h flight to DXB. The 332 C gets to your nerves if you are sitting in it for real long haul.

Watch out for the loads on MUC-DXB using airtravel.tk. If they don't sell enough tickets in F, EK usually seats C pax in F with reduced F service and allocates the C seats to Y pax with Y food service in C trays. ^