Thinking about trying a shorter windshield on my '05 for the summer months, and also thinking about cutting down a stock shield to get a shorter one. Would any year work?

Yes all years remained unchanged; there was a tall version offered from Kawasaki as an after purchase option so other than that all the same.

Yes all years remained unchanged; ...

Mostly  The 1986 model year had lower bar risers, AND a lower windscreen to match. After that, the bars were raised (think ape hangers if you came off a '86), as well as the windscreen. About an inch on both items.

The mounting holes are the same across all years though, and Kawasaki did sell a 'tall' windscreen, so I'll give ya 2/3 credit

Rick