I am sorry, did not read your thread clearly enough...

Last year we flew to DBV. We could not land due to heavy "Bora" fall winds at the coast. Then an additional medical problem on bord took place and we flew back to MUC. Been rerouted MUC-FRA-ZAG as last option of the day. We flew with a big delay to FRA. I've already seen us to stay over night in FRA... But we were picked-up at the arrival gate and have been bussed to Schengen emmigration and then direclty to the gate of the plane to ZAG. Must say, was a very nice surprice and that happened in FRA ^ ^ ^! So just relax, hope everything goes right. And mind, you can not plan delays and interruptions, but you will definitely be in good hands!

With your routing, ORD-FRA-MUC-DBV, you need to clear immigration in FRA and emmigration in MUC. But usually no big deal!