If the earth was infinite, mass would be infinite, therefore gravity infinite (gravity increases with mass - of ANY object)
This clearly breaks any law of physics, the universe would collapse into itself.
No.
Then how did the ice wall get on there if no one has ever been there or seen it?
They have; it's commonly referred to as "Antarctica".
Your FAQ states otherwise:
A1: In the general model, there is a vast ice wall that keeps the water where it is. The ice wall is roughly 150ft high. This also explains why you can find a vast plane of ice when you travel south. Antarctica as a continent does not exist.
Which is impossible to reach because:
A: Only those connected to the Conspiracy have access to heights from which the shape of the Earth can be discerned. Also, nobody has been to the edge of the Earth and lived; conditions on the Ice Wall get increasingly treacherous the further you get out, and navigation methods become unreliable that far south. It is also possible that the Conspiracy is guarding the edge to prevent people from getting too close to the truth.
And agreeing with the above, if A (Area) would be infinite, then mass too would be infinite. Are you suggesting that the earth has infinite mass?
Yes.
With a density of?