7:10 ADR would really be difficult to make if Fantasmic is at 6:30. Fantasmic is 25 minutes long, and then it can take 15 minutes just to get out of the theater & down to the end of the street...it's you and 7000 other people leaving all at once, lol. They'd be lucky to be at that main intersection of Hollywood & Sunset by 7:10, and then it's another 5-10 minute walk over to Sci Fi and allow time to get checked in. I'd stick with a 7:30 ADR. There will be a whole restaurant full of people, there will be a bus. It might stop at more than one resort, but they won't be stranded.