Update:
For the game with PHASER to match the screen size of the game, use this command in jQuery/JavaScript to put the CANVAS on the same layer (HTML/DIV) as the characters:
$( "div.layer.0_fore.layer_fore.layer_camera" ).append( $("canvas") );
Always place this command after the PHASER/GAME script.
Attention:
This may interfere with LIVE2D and other things that use the CANVAS.