Hans,
I have to be a bit of a nitpicker on your group habitation question. There are sites of groups of huts constructed from mammoth bones in eastern Europe going back into the Ice Age. Also there is evidence of groups inhabiting caves much earlier. Basically humans have always lived in groups. You are going to have to be a little more specific.
Catalhoyuk was one of the largest neolithic mud brick villages but there are many smaller villages that were earlier. There are many 'temple sites' much earlier than that but there is very little evidence of any dwellings. The Natufians were building villages east of the mediterranean at the end of the ice age.
On the walled village; Jericho is certainly old but the 'city wall' was a later addition. Basically I am saying that it is not certain that Jericho was the first to fortify.
