When south and west of the Odra belonged to the Habsburgs, the north and east belonged to the Poles.
Not really, I mean the river was always Silesian river, some northern or southern parts could be now and then close to borders but I don't recall circumstances to fit your descriptions.
Certainly Wroclaw as a whole belonged to whichever country Silesia belonged to. No borders on the river Oder dividing Wroclaw in two.