I'm no expert but the first one looks like Cymbalaria muralis. I suggest you use that as a lead to verify the identification. It is quite common on old walls. It is supposed to be edible and to have healing properties. Really make sure you have the correct plant in front of you.
The second one looks like something in the dandelion/thistle family. I'm pretty sure we had that weed when we lived in the city. Maybe it's a type of sowthistle? I don't know if it's edible, though...