I have always found devils hand to be one of those "it will or it won't" corals depending on the exact species. Many are quite adaptable, while others will typically start necrosing fairly quickly from the base upward and often develope black line. Keep an eye out for both. Placement should be med-low water flow and high light. They can shed pretty good as well so be sure you can help out when it needs to remove the outer layer. Make sure it has a wide growth area and not too near adjacent corals.
The sponge is iffy most times, I'm actually hoping this is a chili coral and not a true sponge. Sponges as a rule do very poorly in captive care. They should never be exsposed to air and best kept in an area with high flow and little if any (direct) lighting. Except for blue sponges, most are strict filter feeders and need nutrient from the water. Be sure not to use large particle foods like Marine snow and the like, they will clog the pores and cause the sponge to necros. Live phyto a few times a week will be your best bet.
Orange snail sounds rather ominous, typically it's a moon snail and not really a good reef snail. Can you post a pic?