Information based on an ill-gotten wiretap would be considered 'fruit of the poison tree' and would not be admissible in court. No evidence then to trial and nothing to be acquitted of.
Yes, but attempting to use it would verify that it was collected illegally, making the collector and all in subsequent possession of it accomplices at a minimum, or possibly a conspiracy. Can you imagine the uproar that would occur if Trump was able to use that info to uncover a treasonous conspiracy (some might call it a "secret society") in the DOJ?