For The Lighthouse, it seems pretty clearly to be a weird comedy; I wouldn't call it a horror film at all. Both times I've seen it, the audiences responded with a lot of laughter.
Re: vision of hell - Pattinson's end is a Prometheus riff. Once he gets into the lighthouse (light/fire), he ends up stuck on the beach with seagulls picking at his intestines. Definitely a version of hell.