It'd be really fucking bad, a lot of folk were looking for excuses to assault the local African American population. This would be it.
Fucking grim is the answer but I dont really see that happening. A lot of African American's knew how vulnerable they were and how outnumbered they were. Mob justice wasn't an option, that sat with the White Majority. Most minorities within an environment as virulently hostile as the American South know their survival sadly depends keep their heads down. Violent solutions simply weren't an option to attain justice.
Pretty much yeah. That's pretty much the same reason that Dr. King later went with peaceful non violent methods. Beyond any moral superiority it was really the only available option. Pretty basic rule of a fight is to not fight it the way you're opponents want to fight. White America massively outgunned, out manned (in terms of population numbers 13 percent of the US was black and at the time the overwhelming majority would be considered white today), and out monied black America.
At least in the 60's the US government also had one of the two strongest security apparatus/ militaries on the planet. It's just not an environment where something like guerrilla warfare is going to succeed in. Guerrilla warfare also generally succeeds when they have a powerful patron funneling money, guns, and advisors in to help (such as the Soviets in Vietnam or the US in the Soviet Afghan War). In the 20's and in the 60's they're not going to find that anywhere.
Frankly there were much better odds for Indian revolutionaries against the Raj (instead of say Gandhi's non violent tactics) then there would be for theoretical black revolutionaries in the US of either the 20's or the 60's.