This would be better asked in the Modding board. However, I'll give what info I can here.
As far as I know (and I haven't really tested it) most of the different ethics levels don't really translate to anything specific in terms of gameplay; they just set what kinds of things the civ is willing to do, as well as its disposition to other civs. The exceptions are PUNISH_SERIOUS and PUNISH_CAPITAL, which do have immediate gameplay effects: they allow punishments for various crimes, a beating in the first case and an execution in the latter.
Going case-by-case:
PERSONAL_MATTER: civ members will do this if they want to. I don't think it looks much different than ACCEPTABLE in practice.
JUSTIFIED_IF_X: I'm not sure these do anything specific. Maybe SELF_DEFENSE restricts initiating hostilities, but I haven't seen that.
ONLY_IF_SANCTIONED: maybe this allows the player to designate neutral targets to be attacked by a squad--but now that I think about it, can't you attack your own merchants as well? which would be ENTITY_MEMBER, not NEUTRAL...
MISGUIDED/SHUN/APPALLING: MISGUIDED seems to be the cut-off for whether a civ will accept something at all or not; other than that it (and the other two values) don't correspond to any specific behaviors.
PUNISH_X: SERIOUS and CAPITAL dealt with above. Pretty sure the others have no effect in gameplay (or in world-gen for that matter).
REQUIRED: means that civ members will always do this whether they want to or not. This is why Goblin bards in the current version always end up attacking their hosts, because Goblins have KILL_NEUTRAL set to REQUIRED.
In more detail, however: it all depends on the particular Ethic these values are applied to. Generally a value between MISGUIDED and UNTHINKABLE means a civ is unwilling to perform those kinds of actions. A lot of the Ethics only apply in world-gen: TREASON, TORTURE, THEFT, SLAVERY, eating sapients, and making trophies - all of these (I'm fairly sure) have no gameplay actions that correspond to them. The ones that do affect gameplay are: all the KILLs, ASSAULT, OATH_BREAKING, VANDALISM, and possibly TRESPASSING.
Like I say, you're better off asking the Modding board, as they test this stuff more stringently. I could be wrong about some of these, but this is what I have (casually) observed.