1. I advise you to go to court, as inconvenient as it is. I have been to court many times (in California) to fight speeding tickets. Something you may be able to take to court to help you is the EXIF data from the photos on your phone, match those times to the time on the citation in an attempt to prove you were using the device as a camera not a phone. In the court, it'll be you, the cop, and the judge. So it's a three-way conversation and you'll only have a couple minutes to clearly convey your purpose.

2. Don't know.

3. I prefer MINI (basically a small BMW). But, having been around, and in, many 3, 5, and 6-series. I can say this: the newer the better!