I am not a programmer or a technical expert so I can't answer those questions.

If you take a photo with the camera app the leds seem less bright when focusing compared to the "photo flash".

If dimming is not a good idea, there are still possibilities.

For example, turn on the screen 30 minutes before the alarm, fullscreen red->orange->yellow->white with increasing brightness, and 10 minutes before the alarm turn on the camera leds. Of course, for this you would have to place your N900 on the backstand on a white surface.