Hello Anne! Welcome to the Permies forums!
And WOW that is a nice plan! I don't have the experience you do, so I'll leave overall design comments/questions to other more knowledgeable peeps than me. But I'd like to offer a couple comments and ask one question.
Comments: I worked in the power industry (engineering side) for 15 years ("retired" in 2014) and have found health concerns about being around energized electrical equipment completely unconvincing. I'm not suggesting others agree with me, of course. But I worked around energized high voltage equipment (up to 500kV) a bunch. I have know a huge number of linemen and technicians that have worked full time in such environments for even upwards of 40 years with no noticeable ill effects to their health. Actually my dad started at the power company when I was 7 in '83... so the informal survey of workers goes back quite a ways...
Of course if you want to avoid the lines and want keep your animals away from them, please do!! I'm not trying to change anyone's mind I just wanted to share a perspective that MIGHT be helpful :)
And that buzzing is perfectly normal. It's called corona discharge. From the pic it looks like a mid-to-high level transmission line (230, 345, or maaaaaybe 500 kV) so it would be totally expected to get that buzz. When the insulators get wet while they have dust or debris on them they discharge at a higher rate and the buzzing volume will increase. If it ever seems obscenely loud go out and look at it on a dark night (if you're in an area without light pollution). You might see the leakage points actually glowing in the dark! It's the same phenomenon that causes "St. Elmo's Fire" on the masts of sailing ships. It's actually a
energy loss to the power company so they have a financial interest in minimizing corona discharge; that's something you can talk to them about if you want to. My former employer would blast a stream of ground up corn
cob to clean off energized equipment. Pretty cool! And the noise goes away :)
Lastly my question: what did you use to mark up the Google and topo images? I'm looking for something to do that with. Right now I'm using SketchUp, but it's really not meant for that sort of thing. Yet I haven't found a better alternative.
Excited for you! And congratulations on the upcoming anniversary!