In 1968 I was too young to care about the news, so I can’t offer any personal reaction to your ideas. But I might suggest that you take into account one more issue that you haven’t mentioned at all : the draft.
The huge issue in 1968 wasn’t just the war and the deaths of a few soldiers, (many from poor families)…it was the fact that suddenly ALL the boomer kids were facing the draft, and having their private lives interfered with. There is even a thread running right now about the protests.
Did the 1960's anti-Vietnam-war protests achieve anything? - #38 by Alessan
The draft was what made it personal.
If you write an alternative history about LBJ, peace talks, Ho Chi Minh, etc…it’s just abstract theory, the stuff that makes for a good discussion in a political science classroom. Put the draft, (or cancellation of it,) in the plot, and you get personal involvement that might make for a better story.