I have rarely (if ever) run across things as mean spirited as "whale watchers". Maybe a few times but it's often used by people who are making fun of people who like that body type and not the people who like it themselves. But again, at least BBW has a term and you know what to call it when you're looking for it. I enjoy that but I have plenty of porn that falls into that category. I'm always looking to add variety to my collection and I just recently decided this is something I've been putting off for too long. Anyhow. I was initially looking for terminology for body types that fall into the space between "Seriously skinny" and "BBW". All the girls I ever liked had this same basic body type. It's not an unusual shape. It's just not generally given a name so it's hard to look for. It would probably be somewhere between "small" and "medium" if you wanted to be silly and compare it to a things that come in sizes.
I didn't read through any of this, but basically what you're talking is kind of a very specific body type not a lot of women have. It's basically a curvy figure with a thick build that is very toned and athletic. In other words she looks trim and healthy, despite the fact that she's thicker than other women. I don't think there's really a specific term for that, because I don't think "thick", or "curvy" necessarily points to that.