1: yes possible
2: you have actually said something along the line of: you have to have proof of existence if you will belive it to true, so you can not prove i am a AI or A human being, if you do not see me in real.
Your socalled only proof is valid fall on it butt, since you without seen me in real say, there is a chance i am a real person.
Again, you seem to misunderstand the principles involved here. Rational thinking does not require "absolute proof" before something is accepted as the best explanation.
The simple fact that AI is currently not sophisticated enough to pass as a human in these situations alone makes you being real the best explanation, even though I have no conclusive evidence that you are.
And once AI is sophisticated enough to think for itself and learn and pass as a human, then as far as I am concerned how is it really any different to a human in this context? After all, we are just exchanging ideas via the internet.
Now, if we wanted to go climbing together, it would be a different matter.
There is a chance God is real, you just have not seen God nor have any evidence for God not existence.
There is a chance that some kind of supernatural force is real, but on the basis of everything we know, it is highly unlikely.
The god of the Bible (and Quran, Torah, etc) certainly do not exist. No chance. There is too much claimed about and by them that is demonstrably wrong.