Well, I spent a LOT of time researching and learning, but I think I've basically figured out a script solution on my own! Once the script is run, a new menu item appears in the right click menu. Clicking it will find the Paragraph Style in question and open the Find/Change dialog so that I can click "Next" to find more if need be.
Here's the script that I patched together; I'm sure it's not perfect and could be done better, but it works for me.
//https://community.adobe.com/t5/indesign-discussions/add-script-to-context-menu-on-paragraph-or-character-styles-panel/m-p/10814711#M168839
#targetengine "session"
app.scriptPreferences.userInteractionLevel = UserInteractionLevels.INTERACT_WITH_ALL;
main();
function main(){
// Add the new menu item
var theRtMenuStyleListItem = app.menus.item("$ID/RtMenuStyleListItem"),
theMenuName = "FIND this style";
// Remove any previous versions of the menu item and actions.
if( theRtMenuStyleListItem.menuItems.itemByName( theMenuName ).isValid ) { theRtMenuStyleListItem.menuItems.itemByName( theMenuName ).remove(); }
if( app.scriptMenuActions.itemByName( theMenuName ).isValid ) { app.scriptMenuActions.itemByName( theMenuName ).remove(); }
// Create the menu action, menu item, and event listener.
var theScriptMenuAction = app.scriptMenuActions.add( theMenuName );
var theScriptMenuItem = theRtMenuStyleListItem.menuItems.add( theScriptMenuAction, LocationOptions.AFTER, theRtMenuStyleListItem.menuItems.item(-1) );
var theScriptEventListener = theScriptMenuAction.eventListeners.add( "onInvoke", theScriptHandler );
}
function theScriptHandler () {
// Collect paragraph style name from context menu
// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp
var selectedStyle = app.menus.itemByName('$ID/RtMenuStyleListItem').menuItems.firstItem().name.replace(/Edit "(.*?)".../, "$1");
//https://community.adobe.com/t5/indesign-discussions/script-find-paragraph-style-under-the-folder/m-p/12834067#M470616
function getByName(styles, name) {
for (var i = 0; i < styles.length; i++)
if (styles[i].name == name) return styles[i];
}
var doc = app.activeDocument;
app.findTextPreferences = app.changeTextPreferences = NothingEnum.nothing;
app.findTextPreferences.appliedParagraphStyle = getByName(doc.allParagraphStyles, selectedStyle);
// https://stackoverflow.com/q/41824622
var myResults = doc.findText();
app.select(myResults[0]);
// https://community.adobe.com/t5/indesign-discussions/select-text-based-on-paragraph-style-selected-in-paragraph-styles-panel/m-p/9935498#M104979
app.activeWindow.zoomPercentage = app.activeWindow.zoomPercentage;
//http://kasyan.ho.ua/tips/indesign_script/all/open_menu_item.html
app.menuActions.itemByID(18694).invoke(); //opens Find/Change dialog
}
Please feel free to recommend any changes or enhancements if you see anything that could be done better.