Optical view finder requires a DSLR.
Available light only, no flash, indoor shooting also requires a DSLR if you want decent results.
Smuggling a camera into an event where cameras are prohibited is a real bad idea. I used to work with a concert promoter as the official photographer for his events, and I still had issues on a couple of occasions with lawyer types representing some of the talent. You're probably going to get your camera confiscated, and may face legal action as well if caught.