That should be before the majority of the Spring Break Season crowds arrive. Most schools seem to be off in mid-March to mid-April, but there will probably be a few schools that off while you are there. I've been tracking some school breaks in the
2016 Calendar of Events thread and so far, I haven't seen much for that time period.
Bring that you'll be there before the Spring Break Season starts, it does (most likely) mean that the parks will be operating on their non-peak season schedule (e.g., shorter operating hours, reduced evening entertainment schedule, etc.). On the flip side, it should (hopefully) mean lower crowds (although, lately it doesn't seem like there are really any periods with little to no crowds, so keep that in mind).
DCA will likely present the Pixar Play Parade daily. It's a cute parade and can be seen from pretty much anywhere on the route without too much difficulties. I think you can probably find a pretty good spot within the 30 minute mark. DL will likely present Soundsational daily. It's also a cute and colorful parade and can also been seen from pretty much anywhere on the route with problems. Again, I think you can find a pretty good spot within the 30 minute mark. Neither of these parades are "new", so that's why it's generally easy to find a viewing spot when you go during the traditional non-peak periods. No one really knows what the Paint the Night schedule will be after the holidays. You'll have to wait until the mid-January schedule is posted to get a better sense of that one. Right now, front row viewing spots still fill up 1 to 2 hours before the parade starts (first parade) or as soon as the fireworks end (second parade).
In terms of the shows, only WoC, F!, and Frozen at Fantasy Faire use FPs. F! will be dark while you're there (it's on a year long hiatus). I don't know if Frozen will still be popular enough to need FPs or not, so you'll have to wait until close to your date to find out about that one. For WoC, the front row spots in each FP viewing area still tend to fill up very quickly after the viewing areas open up (~1 hour before the show).
In terms of character dining, I think folks recommend the first seating for the in-park locations to minimize the amount of park time spent at the meal. Otherwise, I would go with whatever times works best for your family's schedule. Although, I would avoid making a reservation within an hour of the end of the meal time. There have been some reports that guests missed seeing some of the character if the meal time ended and they hadn't gotten to them yet. So if, for example, breakfast ends at 11:30 am, I would aim to make a reservation for before 10:30 am.
