Need help with showing the full layer.

I like to use the Crop tool because it is more accessible (C shortcut), you have more control, and it’s something you use a lot, so are familiar with it. It’s right there in muscle memory.

I’ve done the same as you, and used Free Transform to show the content.

With the Crop Tool activated, as soon as you click on a handle, it does the same as Reveal All. 

I use the crop instead of Canvas Size for the same reason.  OK, Canvas Size lets you control exactly how many pixels etc., and where to add them, but I honestly can’t remember the last time I used Canvas Size.