Have never needed to and you don't need to use trim removal tools as per the first video above and I've removed more rear bumpers than I can remember. That video makes it look a lot harder than it needs to be. With practice you can remove a rear bumper in about 25 minutes including jacking.I've also seen people spray WD40 into the gaps, not sure what it acheaves and if Steve does it.
Yes, that's how I do it, but for a first timer I suggested removing the arch liners to make life easier on him.You do not need to remove the wheel arch liners. It is sufficient to just losen the back part and fold that aside while using an extension rod to unscrew the hidden nuts behind.
Another tip is also to remove taillights and use a spanner or similar to push and release the bumper from the backside