I did the homework
I'm not sure why I feel so compelled to respond to this mess, but here goes nothing:
#1:
I believe round about 2019/20, but I'm not 100% sure. I wouldn't be surprised if users started transitioning to the new network before full completion. My guess is Seattle Police/Fire will get on first to see how it works.
You shouldn't make suppositions if you have zero knowledge; it makes hobbyists look like scanner bunnies as opposed to well-informed, knowledgeable folks. Everything in your statement was incorrect. Guesses tend to hurt, not help, others.
Per the
PSERN FAQ:
Q: How long will it take to complete the program?
A: Once construction begins, it will take approximately 5 years for completion.
Since construction looks like it started in September 2016 it looks like Scannerizer was just a little short on their guess. Barring any major delays we should expect rollout to be complete by Q4 2021.
Now, the supposition that they will start transitioning as sites are converted has a lot of merit, however it doesn't look like they are starting with the Seattle core. From a project perspective they wouldn't want to start with their largest entities anyway. They would want to start from smaller municipalities (like Federal Way in this case) to practice the transition process and identify any major problems before tackling larger areas like the King County Sheriffs Office (KCSO) or Seattle PD. The largest entities will most likely be last, but the fastest to transition once they start.
#2:
It will be a P-25 Phase 2 system. How much will be encrypted I don't know...
They actually posted a document named
PSERN Project Radio Features List. Reading this document suggests that only the Government radios will even support encryption. Law enforcement, fire, and EMS channels should remain unencrypted.
DISCLAIMER: I am in no way affiliated with the government nor an expert on this topic. I do not believe the government is constantly out to get us, but I acknowledge they have bad apples. In general, and especially at the local level, the government is full of fallible people just like you and I. Not everything is a conspiracy.