For children, a smaller 4- to 5-inch container with a single plant would be more appropriate. They can watch as the plant multiplies with daughter plants.
One very good place to plant succulents outside is in rock gardens and in stone walls. They grow very well when tucked into spaces between rocks. Some sedums or stonecrops make good ground covers.
Echeveria is the most popular variety of succulents. Plants grow in rosette form. They are often referred to as “hen and chicks” because they develop smaller side shoots. Colors range from blue to pink, red and purple. Morning Beauty is light blue with pink tips. Chroma is rosy red. Lipstick has pointed green leaves with red edges. Black knight has deep purple leaves.
Sempervivum has a similar rosette form. Kalanchoe, crassula, aevium and sedum have attractive flowers. Christmas cactus (schlumbergera) is actually a succulent that blooms heavily.
You can usually find a selection of varieties of succulents at full-service nurseries and garden stores year-round. I recently noticed a nice selection of succulents at Hi-School Hardware in Minnehaha. Extensive selection can be found online.