No, butternut squash isn't pumpkin. It's a squash that's sort of pear-shaped (kind of like an hourglass) and is light brown in color. It is considered an unfavorable carb. I believe pumpkin is also considered unfavorable, but am not sure. Dr. Sears did list it in an article he wrote about Thanksgiving dinner as an OK thing to eat, but that is probably not referring to an everyday thing.
The veggie crumbles they refer to are (I think) a Morningstar Farms product that are made of soy, and designed to taste similar to ground beef. I haven't tried them, as we prefer to use meat, or to use TVP, which is texturized vegetable (soy) protein.
Spaghetti squash has nothing to do with tomatoes. It is a large, elliptical yellow-colored squash, that when cooked will break into natural shape that is similar to spaghetti (kind of like shreds--we pull it out with a fork) rather than the mushy texture of most other hard squashes. It has a faintly sweet taste, and is considered a favorable carb. My husband and I do like it with spaghetti sauce (tomato sauce) and chicken with some other veggies added, like mushrooms, onions, garlic, etc. One thing, though--it's really hard to cut the squash open before cooking!
You can find the block values of many of these foods by doing a search on Dr. Sears main page. There is a great list in there that is handy to have printed out and posted in your kitchen for easy reference.
Hope that helped!