Drying (up of) bottom leaves can mean a lot of different things. Often, it's just natural senescence.

First, to remedy the excess water in your pots, you can use a wick to drain them and/or take the pots to the sink, hold them at eye level, move them downward quickly, then very smartly reverse their direction upward. This uses Newtons first law of motion to force water from the pot. When the water in the soil is moving downward, it tends to 'want' to keep moving. When you reverse the pot's direction upward, the downward-moving water in the soil keeps moving downward and out of the pot.

Everyone (almost) thinks that adding peastone or similar improves drainage and aeration, when in fact it has very little impact on either. It also has an insignificant impact on the ht of the perched water table (PWT), which is an extremely important consideration when you're growing in shallow containers, as many bonsai pots are.

To illustrate, picture a quart jar half full of sand or pudding (S/P). Start adding BBs or marbles to the S/P. Can you see in your mind's eye how the fine particles simply fill in around the BBs/marbles and how they have no impact on the soils drainage, aeration, or PWT? It's only when the BBs/marbles become a very large fraction of the whole that you start to see any notable improvement in drainage, aeration, and ht of the PWT.

In order for you to realize an improvement, your soil needs to be based on a significant % of larger particles than I'm guessing were in the packaged soil you used. Again, this is especially critical when growing in shallow containers, which are much more difficult to grow in than deeper containers. If you're using a soil that supports 2" of perched water and are trying to grow in saucers or other shallow containers like these,
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After you water, most or ALL of the soil will be entirely saturated, which you already recognize is not a favorable condition.

Al

Al is an expert on soil! When you have time, do a search of this Forum and read about soil. It will help a lot. When I first started, I did pretty much what you did, but have learned how to improve my soil. My plants are much happier.

You can bring the plants you are concerned about indoors until the rain storm passes. Could you post a photo so that we can see what your plants look like and which succulents you have?
Penny

Here is a link that might be useful: How to post photo