Youtube Player API hide controls, hide info, hide related videos?

This works fine for me:

player = new YT.Player('divId', {
    videoId : videoSrc,
    playerVars: { 
        'autoplay': 0,
        'controls': 1, 
        'rel' : 0,
        'fs' : 0,
    }
});

You can set 'playerVars' in the second parameter of "YT.Player": https://developers.google.com/youtube/iframe_api_reference#Loading_a_Video_Player

YouTube updated their policy. After September 25, 2018, "showinfo" parameter is deprecated and ignored from iframe.

https://developers.google.com/youtube/player_parameters#release_notes_08_23_2018