I think my lifters are shot

Just run the car for a while. It may take some time to refill the lifters up with oil. You would think that they would fill fast with the oiling system being under pressure. I let my Duster sit during the snow. (It's outside) I started it up and it made a racket for a bit. I just let it protest a bit until the lifters pumpes up.

I really would not worry a bit on magnetize-ing anything for the amount of time you'll have the magnet on the lifter.