Same type questions I have....
It is possible to remove a non-OD transmission without removing the engine (though I don't know why ahybody would want to do so) - but it
IS NOT possible to do the same with an OD trans (oh, if you want to cut your body cross members out, you can force it - however, its not worth it.)
Here's a tech tip on pulling the non-OD trans by itself...[HINT: Get the car about 3 feet in the air before trying it!]
https://www.theautoist.com/pulltranny.htm
...& another way to remove the trans by itself, once its free from the engine, is to rotate the entire transmission 1/4 turn so you can remove the 'shift tower'...then, after rotating the transmission back to its normal position, you can drop it without moving the engine (a bit harder than the above tip though).
However, having done it once, I guarantee you I'll never ever do it again!