Morally, you should've let all of these people die, except the last one.
From what I can assume, your difference is on whether they’d harm others. I’ll assume your creed is libertarian, though there are multiple essays where respected libertarian philosophers have argued that libertarianism doesn’t allow you to give up your liberties (e.g. suicide and indentured servitude)
The fact that these people could be talked out of their suicides (and in fact that some wanted someone to talk to lest they hurt themselves) shows they clearly were having a temporary lapse in judgement. If we accept utilitarianism as the basis of libertarianism, living another day with a clearer state of mind increases utility.
The last one is bad because those people unfortunately chose to live that day.
People should have the right to die, but you're basically saying that people shouldn't be allowed the option of talking things over with a sympathetic listener before making a final decision.
Edit: I have attempted suicide before and self harmed many times. I dated a woman who attempted 12 times.
It turns out life can get much much better. I haven't self harmed in years, she's very happy and hasn't either.
It's very hard to know what living well feels like until you've done it. It took years but I like waking up in the morning.