I haven’t seen the new DL Fantasmic (with the Pirates replacement), but the old one was much, much better than the one we have at WDW. There are some portions of ours that are completely different to DL though, so if you are interested in seeing another version maybe it’s worth your time. The finale is mild compared to DL- the characters are on a much smaller, plain white two deck boat made just for Fantasmic.
Nearly everything at MK is at DLR, so I would go to a different park. Park hopping takes so long it’s really not worth it for a one day visit.
Reserve fastpasses asap; make them for rides, not shows; and make them back to back, starting about a half hour to an hour after park open. Hit headliners you don’t have fp for or want to experience more than once before you use your first fp. Use your second fp at the beginning of the window and then immediately start trying to move your third fastpass to start sooner. As soon as you tap in for your third fp, schedule a fourth, etc.
A lot of DLR regulars like to visit AK as the only crossover was A Bugs Life and the generic spinning ride thats at so many parks. If you all love Toy Story, Star Wars, and shows, then maybe Hollywood would be better. The ride wait times plummet during Fantasmic.