I'm thinking we need to find out more about Paragon. Evidently, the tissues are important for tracing the identity of the heroes. After they got the stomach the identified Barry Allen (or confirmed it), they confirmed Arthur after getting the eyes, etc. Evidently, Paragon was assembled from tissues matching that of actual heroes. Maybe the tissues were cloned, or else they came from some alternate reality where the heroes were vivisected or something.
After this arc/season is over, I'm guessing the next one will be tracking down who assembled Paragon to start with, how they got the tissues samples, and what they are up to now.