CHOROSZUCHA: Probably originated as a nick for a sickly person (chory=ill, unwell)
TARASIUK: Ukrainian patronymic nick meaning Taras' son
KOSIOREK: toponymic nick from localities such as Kosiory, Kosiorów, Kosiorki, etc. Possibly derived from kos (blackbird) or kosa (scythe)
WRÓBEL: sparrow; possibly a toponymic nick for someone from Wróblewo (Sparrowville)
BUCZKOWSKI: from buczek (diminutive of buk=beech); toponym from Buczków or Buczkowo (Beechville)
ZALEWSKI: topographic nick for someone living on a lagoon (zalew) or toponymic for someone from Zalewo (Lagoonville)
MILANOWSKI: toponymic nick for someone from Milanów or Milanówek; those localities were probably set up by nobles named Milanowski.
There were nobles amongst the bearers of the Kosiorek, Buczkowski, Zalewski and Milanowski surnames, More info at: firstname.lastname@example.org