They look like aphids. Mealies are white (or pale grey), not black.

I've looked up aphids and have read that Murphy's oil would work. Is it ok to spray both the leaves and the soil and is it ok to spray all my succulent plants to keep the aphids from spreading to them as well?

I don't think Jades will be OK w/ Murphy's oil soap, am guessing, but personally, I would not do this. Don't know if alcohol will kill the aphids, but I do know it won't kill the Jades.

I suggest your read abt specific pest control for Crassulas (Jades) before you apply anything.

I've never tried it, but I have read that Safer's Insecticidal soap is safe for jades. I've seen it in nurseries, so it's probably easy to get. It will kill aphids.

No, wait! I'm sorry, I misread. Safer's Soap is NOT good on jades. Sorry...

I think plain old palmolive dishwasher soap mixed with water and sprayed onto the leaves will work perfectly fine, I've tried it on echeveria and other species that have a waxy or powdery coating on the leaf and it has been safe.

Where there are aphids, there are usually ants, so try to control the ants as well.

Or bring in some ladybugs which will eat the critters!