Those are Macropharyngodon meleagris, or Meleagris Leopard wrasse. They do get a little large for a 50 gal tank. Often, when fish are in too small of a space, they can get aggressive. They should do well together. As long as they don't injure each other, and keep each other from eating, they should be fine. Leopard wrasse sleep and hide in the sand, so you must remove one if it cause the other to hide in the sand during the day.
I cannot tell from the picture, but they need a fine sand bed ti rest and sleep in to thrive and do well.
You should search and read about the animal you are going to buy to make sure they will do well in your tank. 50 gal is a rather small tank. Even if it is not optimal, at least you need to read about the animals you want to keep.
Good luck with them.