I think it is a bad idea
Bathroom for ads initally look to be a great idea as you said, people who sit there will have nothing to do but read the ad. But economcially it is not efficient, even for toilets which has a high people flow, how many people will be able to see the ad in a day? maximum 20-30 people, if you compare that with ads in metro station bus station which is seen by thousands of people everyday. It seems obvious which ads location firms prefer. Add to the fact that there will be a limiting amount of products which is willing to advertise in toilets, as ignorant as it sounds, ads in toilets doesn't give out a good image to the potential buyers.
About mag stand, I am sorry i am objected to that as well, it is true that there are people who will be enjoying in the comfy area of toilet, but realistically, how many people will be doing that out of the no. of people who just go to toilet to take a shit.
That is my two cents