The backsplash belongs to the counter; so to the edge of the counter. In your case, it's really a toss up as it less than half inch difference. As far as what to use for the edges, what trim pieces does the line have? that will help to decide.

It depends. Some jobs might look better aligned to the cabinets and some to the counter. Get some Quake/Sticky putty (I like Alcolin brand) and stick up a bunch of tiles on the wall, step back and take a look. Rearrange tiles in other pattern, step back and take a look again. Which looks better to you, in your own kitchen?

Whatever you do, do not just leave cut tile ends at the visible edge of a tiled surface. Big no on that one! Either use a matching bullnose edge tile, a pencil liner, a small quarter round liner or Schluter edge.

I would do a schluter edge .It practacally disappears

I would want bullnose edges on those that are exposed. I good tiler should be able to plan the layout and size. Some tiles would probably need to be less the actual size.