GF3 video questions

1) If I'm shooting Aperture priority and start a video, will it use the f-stop selected for stills, or do I have to use Intelligent Auto+ "defocus control" to control the aperture?

2) "Flicker reduction" lets you choose the shutter speed during video, when and why would I use this?

3) AVCHD file naming resets to 0000.mts after formatting the SD card, any way around this?

Thanks,
Matt