All except the hard parts on the ends.
The flowers are edible, the "meat" of the fruit is most often eaten, the seeds are edible and often quite good roasted and salted. This depends of course on the squash i question, there are thousands of varieties.
Gourds are edible, about like a squash.
I do believe that pumpkin flowers are edible, and can be substituted for any squash flower recipe.
yes you cook them just like pumpkin seeds
As spaghetti squash is a Cucurbita pepo and a banana squash is a Cucurbita maxima, they will not cross. Only cucurbits within the same species will cross-pollinate so you can grow one of each. Incidentally, the fruit of crossed species is still edible, but often inferior.
There are many types of edible gourds. Names of them include squash (and several various varieties of it) and Fairytale Pumpkin.
Squash
the part of the flower that is edible
In addition to the fruit, other parts of the plant are edible. Squash seeds can be eaten directly, ground into paste, meal, "nut" butter, or even flour. The shoots, leaves, and tendrils can be eaten as greens. The blossoms are an important part of native American cooking, and are also used in many other parts of the world. Both the male and female blossoms can be harvested pre- or mid-flower.
Most gourds that I am familiar with are from a different genus - Lagenaria. In that case they will not cross with each other. Some decorative gourds are in the genus Cucurbita and will cross. The result may then not be very edible if the gourd dominates. You will get a mixture. If they are edible, it would be when the fruit are very small.
An edible gourd, the flesh of which may be cooked and eaten as a vegetable.
Squash grows from the flower of the plant.