Answer is, it depends, because
The question is somewhat ambiguous, I think, so I didn't vote. Let's analyze this option:
No, lethal force should only be used within the limits established by law.
Now, if one takes that sentence to mean: "If one uses lethal force outside the limits of the law, for example, to protect the life of a dog, then should a person not be punished because the act is morally justified, as may be decided by a jury" (i.e. suggesting jury nullification), then no, I have to disagree - the lawbreaker should be punished. Jury nullification is only appropriate when the law in question making the defendant guilty is itself clearly unconstitutional. That is certainly not the case with the current law of deadly force. So, no, all joking aside, the "he needed killin" defense should never prevail. Too many innocents have died that way over the centuries.
If one takes that sentence to mean, what I think you meant, quite literally, in a normative sense, "should lethal force only morally be used within the limits set by law", then the answer is, depends on the person, and for ME, the answer is no. I can and would kill someone to stop them from killing my dog or setting any dog on fire, *if* and only if they are caught in the act. My own personal morals dictate that value system. But does this mean or imply that I shouldn't be punished under the law as a murderer? Absolutely not! I can and must accept the consequences of my actions as illegal. We are a society of laws, and the rule of law must be upheld. I should try to work within the legislative system to change the law, if I should so choose, to get the allowable use of deadly force to include "defense of dog about to be set on fire", but until I do cause the law to be changed, I must accept that my act would make me a murderer, and I must accept my punishment as a murderer. To do otherwise would be anarchy. I certainly would still shoot the bastard if caught in the act however, consequences be damned. I would however, try to present a defense of "heat of the moment, under extreme provocation", which in my state and most states can reduce the verdict to manslaughter insted of murder, *IF* the jury agrees. But no way should I escape the brunt of punishment for at least voluntary manslaughter, which would be a number of years in the pokey.
In any event, I don't think moral vigilantism should EVER be considered morally justified (by definition illegal), under ANYONE's moral system, if they are not "caught in the act / caught red-handed", doing the dirty deed, due to errors of identification, hearsay error, possible deception, etc. Again, even if morally justifiable under any one person's morality system, the punishment must be meted out.