Here is a side-by-side look at the specifications:
For low light, the p700 would be the better choice.
It has a faster lens rating (when zoomed).
The ISO goes to 640 on the P700.
The P700 was built to compete with the Canon G6 and the Sony V3. That is a pretty nice neighborhood.
All of the cameras you list take excellent photos.
The two Casio cameras have some important manual controls"
The Nikon 7900 is point-and-shoot, so it does not have those manual controls. However it is loaded with scene modes.
I need a camera that can take pretty good shots in low light and take good quality photos and that is compact with pretty good zoom. I am leaning toward the ex-p700 right now but want to hear more opinions about this camera and the two others.