1. Not realistic, but not outside of normal for an management infrastructure/ops position. What you are writing is what you hope for, but sometimes it sends a red flag to potential applicants. The worry many high level people have is that they will be turned into the 'do everything' person. Trim a few of the less directly related requirements off of the description (e.g. Microsoft certification).
2. Yes... but also No. There are a lot of people who push through their careers collecting credentials and turning it another rung on the ladder. Chances are you will get a rosy candidate at some point, who will put in two years of aggressively spending your budget to inflate their resume and then move on. Not that a majority of people are this way, but the filters are set in such a way that this is what you are likely to end up with.
3. Other comments will say 'pay more', but it will be difficult to meet market rates for this skillset when working with local governments. If you can't get approval to raise the comp, instead try to split this role up into a team. Governments won't pay one highly skilled person 250k, but they will pay four people 80k, and one manager 120k.
4. Politically? Find someone with pull, and make sure that it's 'their idea'. Something that they can put on their win list.
Procedurally? Don't boil the ocean. Handle it iteratively. Start with commercial areas and new housing developments. White-glove your initial smaller install and it will create the broad demand from the community to expand it.
Love what you are doing. Hope this helps.