First things first: when you multi-post to the forum, our email, and FB in rapid succession in the hope of getting “instant help” just stresses us out. LightBurn is one dev and two support helpers, and sometimes we do inconvenient things like sleep or eat. 
To your problem:
The first issue I can see is that your calibration picture is tiny in several of the pics you posted. It should be close to the size shown in the sample image. It’s important to hold it very still, so it’s best not to hold it by hand, but to place it on something like a box. The camera doesn’t even have to be mounted to the machine for this part.
The second issue I got from your email - the camera does not look like it’s in focus when pointed at the bed. Have a look at this thread for a great suggestion from one of the forum members: Simple Aid For Focusing The Camera
The camera is focused manually. There’s a small glue dot in the threads of the lens. If you remove that with an exacto knife, or just hold the base of the sensor (not the board) and twist the lens, you can release it and focus the camera. Un-dock and drag out the camera control window to full screen so you can tell more easily when it’s focused. It doesn’t take much of a turn to change it.
And finally, you asked about the corner being cut off. In the preview images you posted I can’t see the corner of the bed, so it makes sense that it wouldn’t be visible in the corrected image either. Try to aim the camera so it can see the whole usable region of your laser bed. This is easier if you jog the laser to each corner then use a small piece of tape or something that you can see from the camera view. Adjust the mounting position and angle of the camera so you can see the four corner marks and that should help. Do this after focusing, but before running the camera alignment process or you’ll need to redo it.
Also, when doing the alignment process, make sure that the top of whatever you’re cutting for the alignment card is at the same height as your laser focus point, and that other things you’re trying to capture are also at that same height.
For example, if you run the alignment process with the paper at 25mm from your laser head, then later you put an object on the bed that’s 5mm high, you need to lower the bed by 5mm to compensate for the added height before you capture (ust set the laser focus to the top of the object again). If you don’t do that before you capture, the alignment will be off.