How to override multiple named textframes only through script

I have a script handy which overrides a textframe in document pages.

Process is, I go the the master page and select the text frame I want to be overriden from the document pages. Apply "bluepara" parastyle for blue and "yellowpara" parastyle yellow boxes.

Here is the overriding script I am using:

function main() {
    var doc = app.activeDocument;
    var sel = doc.selection[0];
    if (
        sel == undefined
        || !sel.isValid
        || !sel.hasOwnProperty('parentPage')
        || sel.parentPage.parent.constructor.name !== "MasterSpread"
    ) {
        alert("Error\rSelect exactly one item on a master page and try again.");
        return;
    }
    var masterSpread = sel.parentPage.parent,
        counter = 0;
    for (var i = 0; i < doc.pages.length; i++) {
        var page = doc.pages[i];
        if (page.appliedMaster == masterSpread) {
            try {
                sel.override(page);
                counter++;
            } catch (error) {
                // item doesn't exist on that page
            }
        }
    }
    alert('The selected item was overridden on ' + counter + ' pages.')
};
app.doScript(main, ScriptLanguage.JAVASCRIPT, undefined, UndoModes.ENTIRE_SCRIPT, 'Override Selected Master Page Item');

The script works fine if I have selected just 1 text frame. It does not work for multiple textframe. Ideally it should.

I am doing it individually currently. After that I run another script to put a particular special charater in that text frame.

Here is the another script:

myDoc = app.documents[0];
var txtFrame = myDoc.textFrames.everyItem().getElements();
for(var i = 0 ; i < txtFrame.length; i++){
    if(txtFrame[i].name == "blue"){ 
      txtFrame[i].insertionPoints[-1].contents = SpecialCharacters.ZERO_WIDTH_NONJOINER; 
    }
}

for(var i = 0 ; i < txtFrame.length; i++){
    if(txtFrame[i].name == "yellow"){        
      txtFrame[i].insertionPoints[-1].contents = SpecialCharacters.ZERO_WIDTH_NONJOINER; 
    }
}

I have named the textframes as "blue" and "yellow". There are other textframes also. I just want blue and yellow to be overridden and populated with the special character.

How can I combine both in a single script and it should work for named textframes "blue" and "yellow" only and ignore other textframes.

I have attached the idml file.