[hamburglar1]

"Since these data are deemed de-identified by expert determination [0] and that’s hazy, if I could reidentify myself after de-id, and I didn’t authorize it, then I could be eligible for breach damages for HIPAA violations up to $50k per person"

The Expert Determination data would likely be released to you with an agreement that you would not attempt to re-identify the data. So if you then attempted to re-identify the data, even yourself, you would be breaking the terms of the license and I would think liable to civil action from the entity that gave you the data (and their upstreams). I don't think you would win here.