If you can upload photo(s) of your succulent pot, I'm sure some of our knowledgeable cacti/succulent growers will be able to identify them for you.
Does the container have drainage holes in the bottom? With some plants, yellowing leaves is usually a sign of over-watering but yellowing leaves can also be due to the soil at root level remaining too dry. Seeing photos of the plants and knowing the type of potting media being used may help determine what the issue is. Succulents need a porous, well draining soil and if the plants are growing in a dense medium it will cause too much water retention at root level and possible rot.