All these elements have a role to play in plants even if they only need to be present in minute amounts. You can look up charts on what plant leaves look like when suffering deficiencies. Most of these can be corrected just by adding correct fertilisers. But sometimes high or low pH can affect take up of elements even though there's plenty present in the soil. Sometimes an over abundance of one element can prevent the uptake of others. It's all a balancing act. I don't know about being "more knowledgeable". Know about some things, but don't know about a lot of others. You know the old definition of "expert"? "X" = unknown quantity "spurt" = a drip under pressure.

1: this is a succulent called a ghost plant 2: this is rotted from overwatering. 1.5 weeks is too often to water succulents like this i go weeks without wayering them. i would cut back to like once a month on the watering. i literally fixed this exact problem 5 minutes ago on my ghost plant (same as yours) that looked almost exactly like your picture. succulents are from the desert and hold water in their pedals and dont need/like a lot of water. they do however like LOTS of sun. 3: how to fix… take the plant out of the pot, cut the rotting part of the stem off maybe like a half inch abpve where the rotting starts. you want a nice healthy stem to replant, so cut it high enough above the rot that youre sure it has no rot left on it. then remove a couple pedals from the healthy top and replant the succulent, making sure to bury the nodes where you removed the healthy pedals… those nodes will grow roots if burried in the soil. then put it in the sun and cut way back on the watering. like i said i literally did this a few minutes ago because one of my three ghost plants looked almost exactly like your picture. i was wondering out loud why only the one was having this issue and they are literally all the same plant (two of the three are peopogated from the ”mother” plant, the first one i owned and took cuts from to make two more. the mother and one of its clones is doing just fine) and my girlfriend pointed out ”wasnt that the one that got rained on a bunch this summer”… sure enough it totally was. it stinks but you can save it succulents are easy to propogate just cut the rot off and replant. and cut way back on the watering. succulents can go for months without water. hope this helps.

Yes remove all the plants, replace the soil with a 50% potting soil/50% pumice/perlite mix. The soil in the picture appears saturated shiny, succulent soil should not ever look like that.

Of the 100s and 100s of babies, I saved these bulbils - just put the end slightly in the ground and let it do its thing. I tried to get some healthy replacements for the plant that bloomed, and I tried to get any with unusual marking - quite heavily variegated, all green, bi-color. And I potted up over 50 of them to root. (and there's another flat that is missing) The albino bulbils didn't grow, as expected. Highly variegated plants were much slower to grow and they have been slowly reverting to marginated form. The highly variegated coloring is not stable in most cases. I gave a lot of babies to friends, many to the local parks, and we posted a notice on Next Door for folks to come get the babies if they wanted them. These are some of the 20+ babies that were around the bottom of the plant. They are pretty large and my neighbors laid claim to most of those! LOL