Okay I'm working on a pretty long essay thing on the Comma Letter (and much else surrounding it), which is taking a bit more time than I thought, so I haven't been posting much (or at all.)
So meanwhile have this quick historical hamgelica fact:
John Adams actually gossiped about the status of Alexander and Angelica's relationship, writing:
“[Hamilton’s] fornications, adulteries and his incests were propagated far and wide.”
Of course, what Adams describes as "[Hamilton's] incests" could only be referring to Angelica's status as his sister-in-law, as relationships between siblings-in-law would widely be considered incestuous at that time.
So yeah, John Adams (and many others!) believed there to be something between the two of them, whether just to use it for slander, or because they gave off that impression so strongly.