I always think the bedside table is most comfortable if it is more or less level with the height of the bed. There's other advice on bedroom design at House Plans Helper - Bedroom Design

I think so; bed level or lower. If higher than the bed, the corners can be seriously dangerous to the eyes when a person leans over during the night.

I think it's a matter of taste. I personally prefer having it slightly lower than the bed. Have you seen this [Houzz article on bedside tables[(https://www.houzz.com/magazine/32-creative-ideas-for-your-nightstand-stsetivw-vs~470149) ? It's got some nice tips and lovely designs.