I would guess that the average American (I really mean average here, not average among HN posters) will have heard of nothing on that list, but also not heard of any US political violence in that time period.
This. The HN crowd vastly overestimates how unknown these can be on an actual person. Even when they knew about the explosions in the (London) Docklands and in Manchester, they would only knew it to be terrorist attacks, not specifically the provisional Irish Republican Army (unrelated to the Irish Army).
Edit: definitely not the Australian city of Docklands (and not any city named Manchester ouside England!)
I think the [Provisional] IRA is well known in America. Every other American seems to think they are 'part Irish' and I think the average American's awareness of The Troubles is high, at least compared to other foreign conflicts (at least for Americans old enough to remember the 90s at least anyway.) Furthermore 'Irish car bombs' are a tactless but popular bar drink in America, which indicates an awareness of the conflict.
My father has a story about being in Irish bars in New Jersey in the 70s and 80s when Irish men would occasionally come into bars and announce they were collecting the 'Irish tax'. People would chip in a dollar or two, with the understanding that the money would be used to support the IRA in some way.
Occasionally I've met people who wondered where the drink name came from, but everybody else in the room was always quick to explain it. Americans may not know all the nuance and details, but the basics ('there was a violent conflict between the British and Irish, particularly regarding Northern Ireland") really are widely known in my experience.
Edit: definitely not the Australian city of Docklands (and not any city named Manchester ouside England!)