So the answer to both of these is yes but no but kind of.

Your veins have valves in them to prevent blood from pooling backwards along your limbs and trunk due to gravity. Veins aren't driven by the beating of your heart, after all, and the blood is trying to go up against gravity; without the valves, you'd be in kind of a really bad spot.

You can technically use a vein graft to replace a stretch of artery in a pinch -- the valves won't hurt you too much -- but replacing a stretch of vein with an artery would be a majorly bad move.