Some notes.
Stadt and Städtchen = city and little city.
ohne wenn und aber = (no ifs, ands, or buts) without a doubt , ( there can be no argument)
geradezu = more like downright or literally. ( an expressive modifier ) maybe ... an absolute magical experience!
ein paar = some, can be two or a pair but more often just means some or a few
fahren lassen = means to let go of
nach und nach = little by little

So not stopped their barbaric behavior, rather they let go of it little by little ( but same end result)

bombastisch = super!
I don't think the word bombastic conveys the intended meaning of bombastisch, its dictionary definition is overblown like exaggerated. In the context of the song it seems like it wants to say the pie is good. All the evidence indicates this, so the meaning of bombastisch in German ought to have a positive connotation. In street language the word means more like super ! like awesome.

frisieren = I'm not convinced it means that they had their heads shaved, since the word just means they got their hair cut, rather than shaved. But the fact they are at a barber for beards maybe implies this outcome. I'm curious if frisieren has this meaning in other contexts.
I visualize them getting shaved when I hear it myself.