Novox -- very excellent work testing out the camera.
1) It will be interesting to see what impact manually selecting a lower ISO will yield. But yes I agree with your suspicion that the result will be darker images -- non manual Point and Shoots that I've used usually have some shutter speed cap and will just refuse to take any shot longer than the limit, even if the exposure/ISO dictate otherwise. It's probably the same here.
2) There's actually a low-light option in the settings (all the way at the bottom of the A button). You might try giving that a shot. In some point and shoots I've used, even though there's no manual function, the low light setting can increase the ceiling for the shutter speed, opening up a few more seconds of exposure over the normal shooting modes. See if that helps.