Actually, I feel they are pretty consistent and intentional with their language.
Immune > Evade > Resist > Apply
For example - in this situation, Biggs' X-Wing reinforces and attempts to place Target Lock on Ghost.
Ghost is immune. Target lock just doesn't happen. It isn't Evaded (because the attack can't be evaded), it doesn't Resist (because it can't be Resisted), and it can't be applied because ghost is immune. So...Target Lock just never occurs.
Consider phase 3 of the Heroic Sith raid. Darth Traya's sabers are all immune to debuffs. Traya is not immune, but has a very high tenacity, so she resists frequently. If I use a squad with Commander Luke Skywalker (CLS) as the leader, then anytime an enemy Resists a debuff, all rebels will gain 5% turn meter.
When CLS uses his basic attack, he attempts to apply two debuffs - Speed Down, and Defense Down. If he attacks a saber, they are immune. They don't Resist these effects - and so my rebels gain no turn meter. Conversely, if I attack Traya with CLS basic attack, one of 3 things will happen:
1) She will evade the attack. No debuffs will be placed, but neither will they be resisted because the attack didn't land.
2) She will be hit, but will Resist one or both debuffs. My Rebels will gain 5% turn meter for each resisted debuff.
3) She will be hit, and both debuffs will be placed on her. My Rebels will not gain turn meter from his leadership (but will gain turn meter if I have a zeta 'It Binds All Things').
Regardless of what happens when CLS attacks a saber, no turn meter will be granted, because no debuffs are ever applied or resisted. That's the difference of "Immune" and that's why they were very careful to use that verbiage.
