Thats how elections work here in NI, its had some interesting results.I'd be supportive of all 6 suggestions, though the 2 that involve selection by non-partisans seem perhaps slightly idealistic. How do we ensure this in practice?
To deal with partisanship on all levels, I'd make two changes to the electoral process.
One is to get rid of the first past the post system. This approach simultaneously makes any chance of relevant influence very expensive, thus paving the way only for major party favorites, and it turns every location into a ruthless, bipartisan battle for completely domination. In the presidential election, most states ignored, including massive ones like California, Texas, and New York, because is known that they have more of one party than another, so they are presumed to be entirely consumed by that party, and those people are left unrepresented. In the swing states like PA, the two (only ever two) candidates just have to tear at each other until they can get one below 50%, they they have all of PA.
The second thing I'd do is add a single transferable vote. What that means is, you can vote for someone, but also state who you'd like your vote to go to if your first choice doesn't get enough votes to make the cut. This basically makes it impossible to waste a vote. The result is that you won't have untouchable favorites, and you'll probably have far more viable candidates running at any time.