SUCCULENT DEATH, OH NOOOO!

SUCCULENT DEATH, OH NOOOO!

About a month or so ago I bought several GORGEOUS potted succulents from Trader Joe's...really healthy and beautiful, but possibly a little overcrowded (they packed 'em in and arranged them to look REALLY full). Anyway, they were doing just fine, and I think I watered them once or twice, which may have been my downfall. The past two weeks, all my succulents that I bought from Trader Joe's have been turning putrid, wet and rotten––it starts at the roots/base and slowly works its way up. The insides of the plants are just a mass of rotted plant-flesh. My other succulents/cacti seem un-bothered so far. I assume it's some kind of fungal rot but I have no idea how to contain this and how to prevent my beloved other plants from dying. On a separate note, I recently was giving some cuttings of a plant that LOOK like succulents, but I have no idea if they are. They have tiny tiny tiny buds/leaves and grow in a vine format (along one central floppy "stem"), but all along the vine are little roots, and apparently you can just cut them off anywhere and stick them in soil and they'll keep growing. Any clue what they are? I can't take pictures yet but I might be able to in a little bit.
My Bog Garden

My Bog Garden

Feeding time at the watering hole

Feeding time at the watering hole

plant ID for a noob

plant ID for a noob

“snails on snails”

“snails on snails”

Intro and HELP!?!

Intro and HELP!?!

winter garden florals

winter garden florals