Yes just like Gregme said. Although I must admit that I have only ever eaten any as courgettes that had not fertilised. If you catch them soon, they still make nice courgettes. And they are quite a size when they flower, easily 8 inches. Only problem is that they don't make as many flowers as courgettes. If too many were eaten as courgettes, there might not be enough time to ripen storage fruit. And if you let two fruit ripen, they will stop flowering. Perhaps have separate plants for courgettes and for storage trombos.
Yes seeds are no problem. The seed cavity is very small and only at the bulbous end. This means that you have two feet of neck to eat before you ever encounter the seed cavity. They keep exceptionally well. Did not grow any last year or this, but the year before and those kept well into the new year. The last one we ate in May. And that actually had no seeds inside at all. How it kept so well I do not know. They never quite have the rich flavour of butternuts, but as they are easier to grow in cooler conditions, that makes up for it.