Yes, you should have park hours 180 days in advance. They seem to be released currently around 6 months + 2 weeks in advance. As for
MNSSHP, I'm pretty sure all the parties are announced more than 6 months in advance (earliest parties are in September, so that would be March and I think they usually announce at least that early).
Just be aware - Disney often changes up the schedules closer to the dates, especially if you are going at a crowded time, they may add more EMHs or change hours.