If you are already rebooked you can most likely forget to get rebooked agin. Trying for get on UA or AC for mileage/points purposes is not a valid reason for being rebooked again, as you can always ask LH M&M for ORC (credit of your orignal booked flights). Once you are back, write a short letter to LH M&M explaning what happend/why you got invol. rebooked and that you request to get miles as originally booked. Most likely M&M will comply.