If you are making ADRs this week, does that mean you are going in February? If so, I wouldn't be set on those 3 pool days. You should have a back up plan. It MIGHT be warm enough to swim in February, but it also MIGHT be a high of 50 degrees. Florida winter weather is all over the place. We have gone in the winter and spent park of the week in shorts, and part in sweaters, coats and gloves. Your itinerary is very weather dependent on an unpredictable time of year.
Also, if your DD is anything like my DD when she was 3, the minute she got a taste of the parks, she was no longer interested in the pool. You might want to consider adding park days. Staying at the BCV, you are in walking distance of EPCOT. My DD loved EPCOT at that age (still does at age 9). There are a ton of Princesses and other characters to meet in World Showcase. There is the Nemo Ride, Turtle Talk with Crush, Living with the Land, the Figment ride, the boat ride in Mexico, the Kidcot stations, bands, jugglers, acrobats. There is a Princess meal at Akershus, but what my DD really loved at that age was Biergarten with the German Band and dance floor.
As far as your MK plans, if you are at MK near rope drop, you won't need a FP+ to meet Ariel at her Grotto. You probably won't need a FP+ for her for at least the 1st hour. Her line gets long a little later in the day, but it also has shorter period, you just have to catch it right. We have never gotten a FP+ for her, and we have waited less than 10 minutes for her on our trip since FP+. The Festival of Fantasy parade is great, but if it is swimming weather on your trip, know that area can be hot and can make a kid cranky with no shade and the sun beating down. For us, it was worth it when the FP+ viewing area was down by the castle, but not as much with it in Town Square. Of course, who knows where it will be in February- it could move back by the castle. The rest of your FP+ are all great choices.
Also, unless they have started something new and are handing out Tinkerbell FPs that are not connected to the FP+ system, you can't grab a Tink FP when you hit the park. You are limited to your 3 FP+ until you have used all of them, or the time expires, and then you can go to a kiosk and try to hit a 4th.
As far as your first morning plan, if you go straight back to Ariel's Grotto, you can get your 1st 3 items knocked out in less than an hour, maybe even less than 30 minutes. We have done those exact 3 things at rope drop and been done very quickly. Your issue that could drag it out may be Dumbo, the play area inside is a time suck. Your 3 year old may want to just stay in there and play for a long period of time. We have seen a lot of irritated parents trying to get kids out, and CMs trying to help them by going in and telling the kids it is time to ride. That early in the morning, they may not have the play area open as Dumbo will probably still be walk on, but if they do it is going to be more for playing than waiting as the wait time will be very short. If things haven't changed if you elect to go into the play area when there is no line before riding, they will give you a pager set for 8 minutes- good luck getting a kid out after those 8 minutes though. You might not want to do that 1st thing on your first day. The line will be short, but the question is whether you are okay with spending a lot of time in that play area when you could be doing things like Pooh, Small World, Tea Cups etc while the lines are still really short.
