when I suggested canvas, I though you were also using your tileMap for background stuff like in niffla's knytt and knytt stories.
So I thought you will spawn an entire grid of sprite.
But as you said earlier, you just want to spawn some platform, ennemies and pickup. For that you shouldn't use canvas.
Also newt was just suggesting using an image based map system... (it's one of his recurring obsession :D)