If a ventricular mass that was causing hydrocephalus was removed, but a shunt was still needed afterwards, is the hydro considered non/communicating?

Not necessarily: Communicating hydrocephalus occurs when there has been a previous hemorrhage for a variety of reasons such as trauma, aneurysm, for example, resulting in difficulty in the fluid in the ventricles(water-like structures in the brain) from circulating properly. Thus even if a tumor that was causing obstruction, non-communicating hydrocephalus were removed the flow of CSF may not be normal.

Depends: This depends on if the mass or obstruction was fully removed and whether other obstructive lesions or anatomy is present (e.g. Aqueductal stenosis). If not, then it would be considered communicating hydrocephalus.