These are all different names for basically the same type of bike. Imagine a bike ideal for commuting with an upright position, wider tires, disc brakes and flat handlebars. Most will be sized using the small, medium, and large convention but you may find some outliers. These bikes are often cheap and oddly enough able to fit people more comfortably outside the normal ranges. I work with them and I routinely ride larges and extra larges with no real problems.
I am 5’8” and these bikes should be much too big for me but with the proper saddle height they become just fine. I am not sure if that is a good thing or a bad thing though. Cruisers are more of a one size fits all; you can just get a different seat post and be fine because the bike is not engineered for performance. These bikes are only meant to be ridden a few miles at a time so don’t spend too much time shopping around and not on your bike enjoying the ride.