Do you have to make reservation?

We just walked in with 5 people an had dinner and enjoyed the marvelous Shoh

Yes, you need to do it, ( there are a couple time options)

If it's for a big group of people, yes. To sit at there tables you have to order dinner. But if you want to just drink and enjoy the show, then you can sit at the bar.

Yes. And do it quite some time in advance too. :)