Your friends will be arriving in T1 and you are flying into T2 so I guess the arrivals centre would probably be the best for them. I'd suggest the
airbrau brewpub as it's hard to miss.
http://www.munich-airport.de/EN/Area...nd+restaurants
Personally when I'm hooking up with friends at MUC we always meet at the Hofbrauhaus im Flughafen at the top of the escalators in T2. I much prefer the beer in there.