That’s a rough one! Maybe you should FP FEA, and go to Soarin’ at RD. I wouldn’t want to RD FEA with a group that big, because it’s a lot of walking, and then you have to come back because the rest of WS doesn’t open until 11:00.
Because your whole party can’t do TT, I’d try to get a 4th FP for that one. Are you going the week before or after Easter? The 4th FP will be tougher, but this is what I’d do:
9:00 – 10:00 FP SE
10:00 – 11:00 Character Spot (if you want it)
11:00 – 12:00 FEA
Edited because I forgot about EMH!
Living with the Land, Nemo, Turtle Talk, the Seas.
9:30 SE with FP (if you get behind, skip this until late afternoon)
10:00 Character Spot with FP
10:30 Meet Anna and Elsa
11:00 FEA with FP
Lunch and wander WS.
As soon as you scan in for FEA, start looking for FP for TT. Look in groups of 2 and modify to get overlapping times. If you get your FP for TT in late afternoon or evening, M:S and SE shouldn’t have waits. Others could do Figment with the littles or play in the exit areas of TT and M:S. (They still have that at M:S after refurb, right? It’s a fun one!)
ETA: With a group of 15 and strollers, it’s going to take you twice as long to get anywhere as it would a family of four. I wouldn’t try too much racing around. There are still a lot of people at EMH!