I'll try:
>1. Clones - are there clones among us?
Reasonable.
>2. Demons? Do they exist? Yes, you mention the Bible and it is mentioned there.
Drop the bible. You are a 'demon' too. Difference is you have a physical body.
>3. Aliens such as grays, reptilians - Do they exist?
Obviously.
You didn't evolve on this earth (Assuming you're no neanderthal).
>4. Is the earth hollow?
Not the way it's sold. The 23.5 tilt is a recent development. Entrances can't be at the current poles.
Probably related to planet expansion. Think swiss cheese.
>5. What is the Mandela Effect? Is it real?
Sad to name it after that guy.
>6. Are pleadians actually Angels?
Drop the bible. See #3
>7. What is the mark of the beast and is it still supposed to come? Or has it already been?
Reasonable
>8. Total earth population is 7 Billion? or 100 million?
#1 Implying the rest are clones? way off…
Possessed people are still human, think drugs, alcohol, etc