I had an apple snail in my tank when I put my newt in (spanish rib) . after about 10 seconds of being in the tank, the newt came face to face with the snail, I waited in glee for its reaction, right away it bit the snail's head. The snail's reaction was to shut down on itself, mine was to scream, the newt's head was all the way in the snail's shell and it kept on tossing it this way and that trying to pull it out of the shell. Eventually the newt let go of the snail, I think it was too rubbery to get a good hold on, I thought it was dead (the snail) but ten minutes later it was going around again. It was a memorable moment. They cohabit all right now but the snail is not adult size.
I've read more than once people do not recomend apple snails with newts because they get too big and can clamp down hard on the newt, causing injuries, so I would say don't do it or else plan to move your snail to another location when it gets too big.
Good luck!