Soap can almost always be saved.
1) Riced - keep stick blending. If the stick blending doesn't work, put it on gentle heat on the stove and basically hot process it.
2) Volcanos happen when the soap gets too hot and the heat is trapped in the soap. If you see your soap in the mold start to rise and cracks appear in the surface, get a spoon and gently stir. See if the soap settles down and behaves. If not, stir again.
3) Separation - put as much as you can in the pot or crockpot and heat.
4) Dry and crackly - for that it really depends WHY it's dry and crackly.
Other options are rebatching and confetti soap.
Confetti soap is the easiest and best of these two, IMO. Cut your soap into small bits, mix it roughly 50/50 with new soap, and put it in the mold. Confetti soap really benefits from heat because that gets the old soap soft and melty so it bonds better with the new soap. I made a batch of soap where some of my lye hadn't dissolved, and instead made a hard cake at the bottom of the lye pitcher. I mixed a bit more lye with water and added it, but the soap was soft and greasy feeling. I shredded it and mixed it with new soap with a lower superfat - 3% I think.
Rebatch - this is a PITA. You shred the soap, add just enough liquid to moisten - start with a few tablespoons - then gently heat in your crockpot until it melts. If you have a bunch of different colors, you will probably get brown soap. Also, the fragrance may cook off. When I rebatch, I add coffee grounds so the soap is more interesting and not just flat muddy brown.