Best practice differences in DB options and wp-config between live, staging and local WordPress environments?

Seems like a good list you have going… Just a few that come to mind:

• SCRIPT_DEBUG to false on live and true on staging.
• WP_CACHE to true on live and false on staging.
• ping_sites to empty on staging to disable ping services.
• default_pingback_flag to 0 on staging to not send outgoing pingbacks.
• Maybe install a Password Protect plugin on staging (in mu-plugins?)

If you do the last then it won’t be publicly accessible and you can set WP_DEBUG to true on staging (and optionally even) WP_DEBUG_DISPLAY

Addition – Stripe Add-On for Gravity Forms, API test mode for Staging:

add_filter('gform_stripe_api_mode', function() {return 'test';} );