I am not pre-determining the answer to the question. That there, is just the juncture where I feel it important to know: Is it subjective (or objective) that human life is valuable? Or is there value at all to human life and value an illusion?
For example: If somebody of objective merit(strong, fit and intelligent) were hanging on the side of a cliff about to fall, and a group of somebodies of mediocrity had the ability to save that somebody, but they were Objectivists: Would they save that person? Would they allow that person to fall? If it benefited none of them personally? But overall, that person was more valuable objectively than any one of them. Or would they try to get something in exchange from that person's life?
Another thing: If you did not value your life, would that change its inherent objective value?
There is probably more I could think about, but I think it is an important point about how human life is valuable and from where it gains value. I can't promise my thought is perfect, because there may be knots I need to work out. I welcome feedback to help me work out the knots.
The value of person A to person B is in how the existence of person A improves person B's life.
To answer your examples first:
Your example of "objective merit" is too narrow. Yes, being "strong, fit, intelligent" is of value to the person who is strong, fit, and intelligent, but there have certainly been strong, fit, intelligent villains. So let's fix your example to say that the cliff-hanger is someone of known objective virtue. In such case, your "mediocre" Objectivists would certainly save the cliff-hanger. The question gets trickier if we're talking about whether the virtuousness of the cliff-hanger is unknown. See here for more on that: Should you help a man who's dying in front of you?
"Would they allow that person to fall? If it benefited none of them personally?"
The whole issue is in this question. Objectively, if there is no reason to do something, then a rational person would not do it. But we've already established that the cliffhanger is a virtuous person. That means that saving him will benefit anyone who saves him. The value of doing anything is in the benefit from doing it. Where that benefit is not known in advance, it can be rationally estimated. To ask the question "Is it rational to save a good person if it doesn't benefit you personally?" is to contradict oneself.
To repeat: The value of an action is in the benefit it brings to the actor. Saving a good person is a selfish act. To give some examples, when you save a good person:
The above are some reasons to save a person of virtue even if you don't directly financially benefit from doing so.
The reason good people are valuable is because they are good to have around. You don't save a good person just because you might directly make some money from doing so.
Regarding the valuing of one's own life, two things:
There is a crucial principle in Objectivism called the Primacy of Existence, meaning that something is what it is regardless of what you think about it. This principle applies to everything, including ones own life. The value of your life, to you, is something which you must discover. It's not something which disappears whenever you are in a bad mood and think "life sucks."
The actual value of something to someone depends on facts about the thing and the person. It doesn't depend on the person's feelings. If it did, then value, as such, would be totally subjective. But it isn't.