Merge results of PHP functions as one JSON object

I have three functions, live_event() - the main function, archived_video() - runs inside live_event() if conditions fail and additional_videos() which should be run in all cases and its results appended to the returned json from both archived_video() and the else clause of live_event(). I want to take the JSON from additonal_videos() and merge it to both live_event() and archived_video() into one JSON object. The ideal output would be:

[{"status":"live_stream","data":[{"uri":"xxx","link":"xxx","title":"xxx".//tons of other data]},{"additional_videos":true,"additional_video_1":"iframe code","additional_video_2":"iframe code","additional_video_3":"iframe code"}]

I cannot get array_merge to work

json_encode(array_merge(json_decode(live_event, true),json_decode(additional_videos(), true)))

And I cannot figure out how to get the functions to return data in the correct format to get array merge to work. Is this possible? How do I need to structure my data so I can access the results of each function inside another function and output one JSON object?

On their own, I can call either of these and they return the appropriate data like so:

function additional_videos() {
    //API creds
    $body = $response['body']['data'];
    try {
        $additional_video1 = $body[1]['embed']['html'];
        $additional_video2 = $body[2]['embed']['html'];
        $additional_video3 = $body[3]['embed']['html'];
        header('Content-Type: application/json');
        if(empty($additional_video1)) {
            echo json_encode([
                "additional_videos" => false,
                "data" => "Additional video error"
            ]);
        } else {
            echo json_encode([
                "additional_videos" => true,
                "additional_video_1" => $additional_video1,
                "additional_video_2" => $additional_video2,
                "additional_video_3" => $additional_video3,
            ]);
        }
    }
    catch(Exception $e){
        echo json_encode([
            "status" => false,
            "message" => $e->getMessage()
        ]);
    }
}

this returns: {"additional_videos":true,"additional_video_1":"iframe code","additional_video_2":"iframe code","additional_video_3":"iframe code"}

function archived_video() {
    //API creds
    $body = $response['body']['data'];
    try {
        $archived_video = $body[0]['embed']['html'];
        header('Content-Type: application/json');
        if(empty($archived_video)) {
            echo json_encode([
                "status" => "archive_error",
                "data" => "Archived video error"
            ]);
        } else {
            echo json_encode([
                "status" => "archive",
                "data" => $archived_video
            ]);
        }
    }
    catch(Exception $e){
        echo json_encode([
            "status" => false,
            "message" => $e->getMessage()
        ]);
    }
}

This returns: {"status":"archive","data":"iframe code"}

function live_event() {
    //AP Creds
    $body = $response['body'];
    try {
        $results = array_filter($body['data'], function($item) {
            if(!isset($item['metadata']['connections']['live_video']['status']))
                return false;
            return $item['metadata']['connections']['live_video']['status'] == "streaming";
        });

        header('Content-Type: application/json');

        if(empty($results)) {
            archived_video();
            return;
        } else {
            echo json_encode([
                "status" => "live_stream",
                "data" => array_values($results)
            ]);
        }
    } 
    catch(Exception $e){
        echo json_encode([
            "status" => false,
            "message" => $e->getMessage()
        ]);
    }
}

This returns:{"status":"live_stream","data":[{"uri":"xxx","link":"xxx","title":"xxx".//tons of other data]}