3 is a tulip and should not be fed. Generally they say don't feed anything that comes from a bulb.
4 are dock leaves and shouldn't be fed because they contain a mild anaesthetic.
5 is another tulip.
I'm afraid I don't know about the rest. I get my information from thetortoisetable.org.uk so feel free to check my answers. When I go on walks I check loads of weeds on there and it turns out most of them cannot be fed! :-(