There seem to be quite well set up for diversions there you only have to look at the visitors it receives in the database if it didn't hand around I would suggest it was either a illness or disruptive pax divert rather than a mechanical issue
Must think up a new one soon, slow moving brain trying to get into gear ;)
I would say Lajes is a fine airport for a diversion. Its runway is over 10k feet long and I'm sure its capable of handling the B747 even though I don't have any direct access to the runway's weight restrictions. Lajes also sees many transit USAF aircraft.