I'm not sure Rollo has nailed it. All your translations so far have been far from the mark (mine would have been too, yesterday) for you have been translating the word 'die Schnitzelbank' instead of the probably correct 'der Schnitzelbank.

While searching for the roots to this song I found another meaning of the word 'Schnitzelbank' which was completely new to me. It fits fine here and explains the lyrics beautifully: Schnitzelbank = 'Bänkelsängerverse mit Bildern' ('more or less bad verses for ballad-singers with pictures'). This word has the article 'der' and not 'die'. And now the lyrics start making sense: 'Ist das nicht ein Schnitzelbank' is completely correct German and means roughly 'Isn't that here a succession of bad verses' whereas 'ist das nicht eine Schnitzelbank' would mean what has been posted above.

Der Schnitzelbank in that sense is still well known in Switzerland and in the very south west of Germany as a term for a succession of verses depicting local or global happenings in a humourous manner not only but especially during the carnival season. If you want to read more you have to go here: Woher kommt der Schnitzelbank?

'Schnitzelbank' is related to 'Bänkelsänger', an old German expression for 'ballad singer' . It was to be heard at weddings as well (to kid the persons present) and that might explain the wedding angle in the lyrics.

'Hobibank' in my eyes is an intrusion from singers who were not familiar with the other meaning of 'Schnitzelbank'. If we want to infer the origin of that song from the meaning of 'Schnitzelbank' we have to go to the very south west of Germany or Switzerland or Alsace. These regions share a dialect of German which is termed 'Alemannisch' (I've never seen an English translation of that). And this is the only dialect in German in which 'Ist das nicht ein Schnitzelbank' makes perfect sense and is understood as being correct German.

Not a proof, I know, but a strong suspicion.

Wolfgang