Well, Bella is one of the best and most powerful witches in the Harry Potter universe. Little we know of the fighting ability of Newt, but he is a wizard effortless and without fear some, since it fought against Grindelwald ...
R1: I believe Bella wins, more knowledge of spells, more battle feats, more articulate.
R2: I believe Bella again but not very very easy.
R3: I feel sorry for Newt here, he's crushed.
R Bonus: Bella can survive, she knows more Voldemort and has better preparation to survive even if she can not overcome Voldemort she survives, Newt would last a few seconds here.