Is there a difference between the four terms? I neither know or care. Either I find someone attractive or I don't, regardless of whatever labels others may choose to apply.
Personally speaking, I've never liked skinny girls, but for most of my life, I've preferred girls that could be classed as a little chubby but nothing more. Then a few years ago, I met a fat girl. Not chubby, not "big boned". Just out and out fat. And very, very sexy. Since then, my preference has actively been for larger girls that 10 years ago I would probably have found repulsive due to their weight.
Tastes change with time. Mine did. To my mind, there's no point in spending too much time wondering why. I just go with what works for me at this point in time. So yeah, I like fat girls. Others don't. That's fine. But to my mind, they're missing out :-)