Hi Gambette
I regularly make a Nettle soup, Very easy to make and tasty, can be frozen for later and can be veggie or vegan depending on if you add cream or creme fresh etc. Just use the top shoots and use some thick gloves when picking
Nettle soup try this and then experiment.
The otherway is to treat like spinache and blanche in hot water (don't over cook as they go slimey and add salt butter and a touch of nutmeg.
You can eat all bits the dandelion but the leaves are probably the best bits, However use only young leaves as they get tough and for best results cover plant with an upside down plant pot for a week as the leaves will be less peppery! it is very closely related to chicory
Not too sure about using the rest but as mentioned earlier it is a diaretic, it's old english folk name is pissabed
Hope this helps,