Toki wrote
... is there anything that describes:
# the configuration options;
# what that option does;
# acceptable values for the option;
# the effect of each acceptable value;
For each item listed at ">Tools >Options >LibreOffice >Advanced >Open
Expert Configuration"
If so, what documentation, etc am I looking for, and where can it be
found?
Nope, why it takes an expert 
You pretty much must as you said try:
* Reading the source code, and translating that into English;
* Playing with the options, selecting randomly selecting values, and
hoping I can pickup the effects;
Oh, and take notes, or you'll do it all again. The majority of user
adjustable Expert Configuration stanzas are in *common.xcs* found here:
https://opengrok.libreoffice.org/xref/core/officecfg/registry/schema/org/openoffice/Office
I find that sorting the Expert Configuration dialog by the Preference Name
field makes it easier to locate the corresponding source. For some of the
more obscure *value* settings (without comments in the .xcs) you have to
dig into the corresponding source.
As to the Help, this is all that has been done thus far for using the Expert
Configuration dialog:
https://help.libreoffice.org/Common/Expert_Configuration
<https://help.libreoffice.org/Common/Expert_Configuration>
Or in the actual Help source, and a couple of the Help articles that explain
setting a value:
https://opengrok.libreoffice.org/xref/help/source/text/shared/optionen/expertconfig.xhp
Disable Preview of styles on the Styles deck
https://opengrok.libreoffice.org/xref/help/source/text/swriter/01/05140000.xhp#50
Number of Undo steps
https://opengrok.libreoffice.org/xref/help/source/text/shared/01/02010000.xhp#47
MRU picklist size (and start center thumbnails) shown
https://opengrok.libreoffice.org/xref/help/source/text/shared/01/01990000.xhp#40
Documentation team is always happy for assistance, especially on a large
project like capturing all these would be.
Stuart