Is your parking covered? And is there a size limit on vehicle? I will be traveling with a pet and booking through frankfurt airport parking website- How do I indicate traveling with pet? Can your airport shuttle accommodate a large dog kennel?
Sorry, don't know about parking. The shuttle bus is a large city bus type, so it will accommodate any size of luggage. ( you take your own luggage inside the bus. )
Since you are in Germany, I suggest you call hotel for parking questions.
Get an answer from IntercityHotel Frankfurt Airport staff and past guests.