All are correct! However, in the example, "there is nothing I love/hate so much," it sounds incomplete. It can be correct in the contexts where it is obvious what Person A and Person B are talking about. But if what you love/hate is not obvious, you would say, "There is nothing I love/hate so much as... dogs/lying/broccoli/etc."

They all make perfect sense but they sound a little unnatural when used as responses to questions. Examples: Q: Do you like it? A: Oh, I love it!/ I really like it!/ It's great!/ It's just what I wanted! Q:Do you like it? A: It is ok./ Not really./ No./ I hate it. Q: Don't you just hate it? A: Yeah, it's the worst!/ It's not that bad. Those would be typical natural responses to the questions of like or dislike in American English. As for stating something you could say something like this: There is nothing I love more than sitting on the sofa and reading a good book. It could also be used in response to the question: Q:What do you like to do? For the negative form you could also use it as a statement. For example: There is nothing I hate/dislike more than willful ignorance. This could also be used as a response to a question such as: Q:What do you hate/dislike the most? I hope this helps. :D