Last time we ate at H&V it took us 15 minutes to get seated, so you will want to account for that. After being seated it took us about an hour to eat our meal. So, I would make your PS an hour and a half before the time you want to leave H&V. I would also arrive 15 minutes early for your PS time.
Now, after you leave H&V I'd plan about 10 minutes to walk to the FDP entrance to Fantasmic. We arrived at the entrance about 25 minutes prior to showtime and got good FDP seats. People continued to file in until at least 10 minutes prior to show time. So, if you want a good seat I'd arrive at the recommended 30 minutes prior to show time. However, you should be able to get away with arriving 15 minutes prior if you don't care about your seat.
That being said a 7 PS means you probably have little chance at getting a good seat and you may have to rush your meal. Personally I would move my PS up to 6:30 or, if that isn't an option, I would arrive at 6:30 for a 7 PS and hope to get seated early.
-Josh