i forgot to ask this when i ordered mine, but should be talking to my dealer soonish, so will try to remember to ask them then, cos id like to take my bike with my sometimes and i dont think itll fit in the back even with the seats down.
There's a picture of the up! on the European Accessories brochure with the sunroof and roof bars so I think they will fit - finding the right footpack for the bars however may be a struggle we had a job and a half to get some to fit the Fox
I can get my 19.5" Trek Mountain Bike in the back with the seats down and passenger seat forward a tad. You have to take the wheel off but it's the same in my Golf too! I didn't order mine until I knew I could do this as I went to the launch in Spain and knew I wanted one but had to make sure so took the demo home when it arrived and tried! With regards to the roof rack I'd imagine it would fit as dimensions of the car are the same and in the accessories brochure there's a smart bike rack you can attach. I would double check with the parts dept. at your dealership though.