Because of the matching corner windows I would paint them the same as the accent wall, but it may look like you just never finished the paint job.

I think when you extend an accent wall onto an adjacent wall, you do run the risk of it looking like you're still in the middle of a painting project. I would leave it as is.

I think it looks very odd to have more than one accent wall in a room. My vote is no, do not paint that wall to match the accent wall.

I would have said no accent wall in that room. Paint all 4 walls the same.

I know you didn't ask this, but the brown accent color is making your lovely wood bed vanish. I would do the whole room in the sage. Just my opinion though.