I've stayed at both HKDL hotels - you won't be disappointed with the Hollywood, and you'll still get to see the HKDL Hotel when you go for Dim Sum (which I'm very jealous of by the way!)
The park is seriously practically empty for the first few hours after it opens. I'm not even kidding. Like a ghost town. You will have plenty of opportunity to get your photos on the way through AND walk onto both Mystic Manor and Grizzly Mountain several times in a row. There's no FP for Grizzly Mountain, but you won't need one. I've seriously never seen more than a 20 minute wait (and that was on a Saturday afternoon).
There's really not much to Toy Story Land, but all the rides are slow loaders. You could potentially be better off to head here first then back track to Mystic Manor and Grizzly Gulch. Otherwise, you're really not missing much if you can't be bothered to wait for the rides.
Make sure you get to the theatre early for Mickey's Wondrous Book. We got there about 20 minutes before the show and were turned away both times because the theatre had reached capacity. Shows and characters seem to be more popular than rides over there. We haven't actually seen FOTLK yet, because it's always down for maintenance in March and that's when we tend to go. However, I've heard that it's very different to the one at AK (which I also haven't seen lol!). I would try to go in with no expectations, and no comparisons. Just enjoy the show for what it is.
Flights of Fantasy is by far my favourite parade so far. FWIW it came before Soundsational. I loved the song so much, I was so excited when I got to DLR and I heard the very same music! The parade is much better though - the floats are awesome and the performers are incredible! So much interaction if you get a front row spot too. FWIW we've always got a great front row spot walking up 10 minutes before the parade starts. It's highly possible that you'll want to see it again. Not sure if you're aware, but Paint the Night also made its debut at HKDL before transferring to DLR. I kind of think it's nice that it'll be unique to HDKL again soon. The fireworks are a different style to DLR. More low level and centred around the castle. But I love them!
I would suggest you probably won't need a FP for Space Mountain. I've never seen it with more than a 15 minute wait (and that was a Saturday afternoon). Although now that it has its Star Wars overlay, it might be a bit more popular. The option is always there for you anyway. I can guarantee that you will wait longer to meet R2D2 than you will to ride Space Mountain.
I think you'll really enjoy taking in the theming around HKDL, and the gorgeous mountain/jungle backdrop that is still unique to HK. Also, after TDL and SDL, you will very much enjoy the more laid-back, less crowded atmosphere. It will be a great note to finish on