cut off all the dead parts and root the cuttings

I just tipped the pot on its side and washed all the soil off the roots and then thoroughly washed the entire plant free of all soil. Then I placed the roots into clean water while I sterilized the pot with very hot water. Then I used fresh potting mix and coir peat to repot the plant. I did all of this because my succulent leaves were dying from something? That was about a week ago and all seems well so far. I kept the direct sun off it while it recovers.

I figured that if it's a soil problem then it's best to get rid of the soil completely and rule out that possibility.

Succulents are better off drying out for a few days if you're repotting or taking cuttings. Did you cut off all rotted parts? Rot suggests too much water at some point; what are your watering practices? Also, what was your base potting mix - was it C&S soil? I would add perlite to this, instead of coir.
If you know the names of your plants, or have pictures, that would be helpful also.

Aparlato, since this condition is occurring to all your plants, the blame cannot fall on something about the individual plants.

So.....it has to be something you are doing to the plants...overall.

I must ask a question: Are you on a well, and do you have a water-softening agent ---such as salt to make your water less hard?

That in itself could be the reason why your plants are suffering.

The salt build-up would take time to act on the plants....but seeing as how all your complaints are happening at the same time, I suspect its something that can come about because of something that is being done to all of them.....such as watering them.

If this might be the case; I suggest you do a thorough leaching. Sinks, bathtub and such... since these faucets would hardly be OFF the system, you would have to find a tap that is not.
Or, gather rain-water---or snow....and melt this.
Let the water gain room temperature....then fill a tub or large pot with sufficient water to allow you to immerse the pots entirely in the water. Allow the bubbles to cease.

This serves two purposes: It puts water entirely throughout the soil and if there are any bugs in the soil, they would have to come to the surface to breathe.
There, you dispose of them.
It is also a very good way to thoroughly rid the soil of harmful salts---either from too much fertilizer...or possibly as I suggest...as on a water-softening system.

Treat this as a watering.

Allow full drainage and put your plants in their respective sun.

If you feel it is necessary, you might decide to change the soil instead. A fresh potting soil with lots of vermiculite. Just be sure to not use such softened water from any of the taps on the system.

Usually a home will allow a tap or two to be OFF the system....for watering the lawns, washing the car...etc
This could be thought of....gather water there and hold for plant use.

If you are not on a water-softening system, such a happening to many plants at the same time I suspect still you are overwatering---perhaps you water as per schedule...and not according to how the plants need watering

Your plants....succulents, hold water in their leaves as a resevoir and can take dry periods for a time. As long as they aren't allowed to go completely dry, they should be able to withstand some dryness without being badly affected.

You might, when the first sign of limp....or wilt occurs, give your plants a thorough watering.....to the drainage point. Then dump the excess...never leave your plants sitting in such drainage for any extended time.
Then allow them to dry down a bit between watering.....then water to drainage.