I think saying that it is going to be Lufthansa Regional has said it all already. It's hardly going to be to Berlin or Munich. If they're coming, it'll be some small size jet... i.e. E190 and the destination will be Frankfurt. It could be nothing else. (Unless its a larger aircraft.)
Can't wait to see them at the airport, will provide some well needed onward connections from NI! Hope the timings are good!