As I understand it, he received a transaction from Satoshi Nakamoto. It turns out that he knew him personally or am I confusing you ?) Was he the first person to mine bitcoin after Satoshi ?)
we have no way of knowing whether Hal knew Satoshi personally or knew him like the rest of us as an anonymous person online who only contacted others through emails,...
as for him being the first to mine, i think he was since back then "running bitcoin" was equal to also mining with your CPU and the tweet from Hal Finney is 7 days after first bitcoin block so it is safe to assume he was the first.