You do not need to book after 7:00 and I suggest you don't... Get an early ADR if you can... They start dinner there at 4:00... You can also get into the park with a party ticket at 4:00.... We usually eat at LTT around 4:30 and then have a snack while we wait for the parade.... I have recommended this to several disers for a couple of important reasons:
1) You want to have eating out of the way to enjoy all party activities
2) Between 6:00-7:00 is a great time to hit some rides because the lines are usually short... People are leaving for the day, eating, or just coming in
3) Your wait for a table will be shortest if you have a ADR during the 4:00 hour
**Yes, the characters at LTT have some special extra's on their costumes (masks) to give them the Halloween feel!