Where can I find detailed historical breakdowns of U.S. lightning fatalities on a year-by-year basis? e.g. Something like this, but for historical years (preferably covering 1980-2007, since the NWS detailed lists only start from 2008). Location of strike, victim name, where the victim was at (under tree, out on open water, at beach), etc.

If such a resource does not exist, then what's the next best thing? All the archived meteoroepidemiology (yes I know that's not a word) data I've been able to find is limited to overall numbers of lightning deaths by state/on a national basis.
For a comprehensive literature review of sources of lightning fatalities data you can check the paper "Striking Back: An Assessment of Lightning related Fatality and Injury Risk in Canada", it covers US and Canadian sources. But if you want to know which one is the largest and arguably the best. That would be NOAA's Storm Database. The data you can access trough the online interface is quite limited, so I would recommend to go to the Bulk Data Download area, and get the original spreadsheets. You will see 3 files per year: Locations, Fatalities and Details, from 1950 to 2017. I would recommend to download the "Details" files, as it also have information about the location (Lat/Lon) and number of deaths and injuries, and a short narrative of the event.
It is a large table, as an example, I took the following screenshot of the most important data columns for all the lightning events with casualties in 2009:



You can download the Fatalities file if you want more info abut the age, gender and location of the victim. The relevant fields look like this: