You won't need a u-lock. You just put it into the nearest station. If you want to keep riding you take out another one.

There will be regular maintenance, including air. I took a bike out in Milan last year and found the tires mostly flat. It was a very uncomfortable ride on the cobblestone streets, especially with the tram tracks everywhere too, never mind the trams that you don't hear coming.

The bikes all have dynamo hubs and have always on lighting.

I didn't start seeing them until I was away from the greenway. As for tourists using them, today was for annual members only, so no tourist would likely be one. I'm still puzzled by the rate structure though, there doesn't seem to be a single use price, just daily, weekly and yearly.