Commerce Kickstart: How do I fix a SQL error on string length after using Features Override to save customizations?
Great news! Kind of. 

After looking at the database more (using the Database Admin module), I found that the "info" column is a BLOB. A BLOB has a max char length of 65,000.

Given the number of changes I made to the default settings, my Feature Override complete set of Feature Overrides well exceeded the 65,000 characters allotted. I opted to split the Feature Overrides into individual packets, grouped by type (variable / facetapi / user). This appears to have done the job. Fairly straightforward after better understanding the db setup and limitations there.

In terms of avoiding extensive overrides, I suspect that I created this snag by starting out with the demo store implemented in Commerce Kickstart. That option seemed like a good plan for me at the time because it provided some basic features already setup. I adapted those for what I need, but it may not be a particularly good foundation from which to grow the site. Any feedback there?