As to Mobike, I wouldn't spend too much time trying to get it to work. I finally managed, but it took a lot of time and effort as my photo kept getting rejected.
As well, core Shanghai is not a great place for cycling, though Beijing isn't too bad and a bike is useful for getting out to the far reaches of West Lake at Hangzhou.
Because I'm staying at hotel close to my friend, it looks like I'm out in the Burbs (will be at a Holiday Inn Express on Jinshajiang Road, Putuo District). For exploring the core, me and my camera will be on foot.