For it being a first offense but unlikely that at trial you will get more of a reduction or finding of not guilty.
2. If that’s legal in the jurisdiction, tough. Some jurisdictions may not permit an officer on foot doing radar but I’d bet that’s a minority. Some officers are unfair about where they choose to camp out but most of them choose to go where they know there is problematic speed. If you’re so concerned about the officers safety why were you speeding? And complain to the agency about that practice, having a trial isn’t the place to complain about that unless it’s an illegal practice.
It is entirely possible if you have a trial that the higher speed could be charged and you face a higher fine and/or more points on your license.
Sounds like you should pay the fine or go to traffic school depending on what your jurisdiction permits. Sounds like you were treated more than fairly with the reduction, you just don’t like the outcome and feel like you were tricked.