Can you go at Shoshone Falls anytime even if it’s night.

Yes, you can enter the park until 10 PM (the gates close and are locked at 10 sharp, it says so at the park), however before about 5:30 PM there is a 5 dollar vehicle fee, cash only. Long story short, the hours for entry are 6:00 AM to 10 PM, no exceptions. There are other falls nearby, and they are also beautiful. There are actually a couple that you can walk under. And those are open 24|7. Shoshone Falls does cost money until 5:30, however. Be warned

Not sure, but if they don't have lights it would be difficult to see the falls.

I believe so