24 hours direct transit policy and staying over night

I am a US citizen, and my wife is a Sri Lankan citizen with a green card. We are departing from SFO transiting at shanghai pu dong airport(lay over is 20 hrs and 45minutes), and the destination is Sri Lanka. We are arriving shanghai on july 7th on 5.20pm, and departing on july 8th 2.05pm so the lay over is 20h 45m.

Do you thing me or my wife(who has Sri Lankan passport) need to get transit visa?

Does shanghai pu dong air port close at night? and do we need to leave the air port?

I also heard we have to recheck all baggages at shanghai again is that true?
Can somebody answer me.
Thanks