Seriously, the "no proof" argument is really wearing thin in the 21st century. If someone died and there's no evidence, does that mean he was never alive?
There's no such thing as 'proof' either. There's inference and evidence, supported hypothesis and theories but never proof - except for one a priori logical principle. Proof means that there is absolutely no way to refute the claims and if you actually study critical thinking, there is almost always a way to cast doubt upon a supported hypothesis or theory.
If we have no evidence to say somebody existed, then we have no reason to believe they existed. Why would you assume they did? What would constitute as evidence? I, for example, believe that Jesus Christ actually existed because there is a wealth of supporting evidence but I don't believe that he was the son of God.
Your existence isn't an illusion - it's the only thing that's absolutely and objectively true. It's called the 'cogito'. I suggest you look it up. However, there is no absolute way to 'prove' (in the true sense of the word) that anything you observe, see, touch, feel or experience
is real. One draws a line between practical proof of reality based upon communicated interactions, etc. but actually there is no way to definitively prove that anything outside us exists. As somebody that has in the past suffered from psychotic episodes (hallucinations, visual and auditory) I can assure you that not all you see or hear is necessarily real.
No, there is no such thing as objective human rights. They don't necessarily exist. They are a construct made by humans for practical reasons. They certainly didn't exist before humans. Why the Hell would you use that as an example? Are you trying to say they're woven into the very fabric of the Universe? Bollocks. It's a terrible example if you're trying to demonstrate a point. In the same way, there is no such thing as objective morality, ethics, culinary practise, law, politics...