To keep your tenses consistent, use had for the first case, as it implies that "not seeing a movie like this' is in the past.
For the second case, the first sentence refers to the movie when you watched it, not the movie in general. (Otherwise you would have used "That is a great movie"). Therefore since we are referring to the movie in one of its instances (when you watched it), the second sentence should begin with was. After that, have seems like the logical choice since this phrase I had ever seen is technically describing the movie, and is attributed to the word before it, hence not having its own tense.
However, this is dialogue, and the rules are loosened, particularly because people don't perform this type of analysis before speaking, therefore you are a bit more flexible in this situation.
I know I got a bit technical there; if you need clarification I'd be happy to help.